Eusebia (†360, full name Flavia Aurelia Eusebia, sometimes known as Aurelia Eusebia) was the second wife of Emperor Constantius II. Main sources for the knowledge about her life are Julian's panegyric "Speech of Thanks to the Empress Eusebia" in which he thanks her for her assistance, as well as several remarks by the historian Ammianus Marcellinus.
The primary source on her ancestry is the "Panegyric In Honour Of Eusebia" by Julian the Apostate. According to it, "she [Eusebia] is of a family line that is pure Greek, from the purest of Greeks, and her city is the metropolis of Macedonia". Eusebia was born in Thessaloniki and was a Macedonian by origin. Her father was reportedly the first member of the family to serve as a consul. While not identified by name in the speech, modern historians identify him with Flavius Eusebius, consul in 347. This Eusebius is identified elsewhere as a former Magister Equitum and Magister Peditum, which means he had served as a military commander of both the cavalry and infantry of the Roman army. The Prosopography of the Later Roman Empire considers it probable that his consulship came at the end of his military career. He is later styled "Comes". The Panegyric mentions that Eusebia's father was dead by the time she married Constantius.
The Panegyric says, "Now though I have much to say about her native land". Julian goes on to mention the history of Macedon, identifying her native city, then proceeds to speak of her family. "She is the daughter of a man who was considered worthy to hold the office that gives its name to the year [the consulship], an office that in the past was powerful and actually called royal, but lost that title because of those who abused their power". ... "And if there be anyone who thinks that, because he I spoke of was the first of his line to win that title and to lay the foundations of distinction for his family, he is therefore inferior to the others, he fails to understand that he is deceived exceedingly. For it is,in my opinion, altogether nobler and more honourable to lay the foundations of such great distinction for one's descendants than to receive it from one's ancestors." ...Eusebia, the subject of my speech, was the daughter of a consul".
Her mother is not named but mentioned briefly: Constantius "Judging also from her mother of the daughter's noble disposition. Of that mother why should I take time to say more, as though I had not to recite a special encomium on her who is the theme of my speech? But so much perhaps I may say briefly, and you may hear without weariness, that her family is Greek of the purest stock, and the native city was the metropolis of Macedonia [Thessaloniki], and she was more self-controlled than Evadne the wife of Capaneus and the famous Laodameia of Thessaly. For these two, when they had lost their husbands who were young, handsome and still newly-wed, whether by the constraint of some envious, or because the threads of the fates were so woven, threw away their lives for love. But the mother of the Empress, when his fate had come upon her wedded lord, devoted herself to her children, and won a great reputation for prudence, so great indeed that whereas Penelope, while her husband was still on his travels and wanderings, was beset by those young suitors who came to woo her from Ithaca and Samos and Dulichium, that lady no man however fair and tall or powerful and wealthy ever ventured to approach with any such proposals. And her daughter the Emperor deemed worthy to live by his side".
Ammianus Marcellinus mentions two siblings of Eusebia: "Eusebia, sister of the ex-consuls Eusebius and Hypatius"  Ammianus mentions that during the reign of Valens, both were accused of treason by Palladius. Palladius had "gained leave to name all whom he desired, without distinction of fortune, as dabbling in forbidden practices, like a hunter skilled in observing the secret tracks of wild beasts, he entangled many persons in his lamentable nets, some of them on the ground of having stained themselves with the knowledge of magic, others as accomplices of those who were aiming at treason." ... "I will recount this one case, showing with what audacious confidence he smote the very pillars of the patriciate. For, made enormously insolent by secret conferences with people of the court, as has been said, and through his very worthlessness easy to be hired to commit any and every crime, he accused that admirable pair of consuls, the two brothers Eusebius and Hypatius (connections by marriage of the late emperor Constantius) of having aspired to a desire for higher fortune, and of having made inquiries and formed plans about the sovereignty; and he added to the path which he had falsely devised for his fabrication that royal robes had even been made ready for Eusebius. Eagerly drinking this in, the menacing madman [Valens], to whom nothing ought to have been permitted, since he thought that everything, even what was unjust, was allowed him, inexorably summoned from the farthest boundaries of the empire all those whom the accuser, exempt from the laws, with profound assurance had insisted ought to be brought before him, and ordered a calumnious trial to be set on foot. And when in much-knotted bonds of constriction justice had long been trodden down and tied tightly, and the wretched scoundrel persisted in his strings of assertions, severe tortures could force no confession, but showed that these distinguished men were far removed even from any knowledge of anything of the kind. Nevertheless, the calumniator was as highly honoured as before, while the accused were punished with exile and with fines; but shortly afterwards they were recalled, had their fines remitted, and were restored to their former rank and honour unimpaired." 
Her siblings have been identified with Flavius Eusebius and Flavius Hypatius, co-consuls in 359. Eusebius is described as a rhetor in an epistle by Libanius. In the Panegyric, Julian alludes to both brothers having secured high offices through the influence of Eusebia. Libanius identifies Eusebius as governor of the Hellespont c. 355. He was next sent to Antioch and then appointed governor of Bithynia. He held no known offices following his term as consul. Hypatius was possibly vicarius of the city of Rome in 363. Libanius mentions Hypatius appointed Praefectus urbi, c. 378-379. Gregory of Nazianzus mentions Hypatius visiting Constantinople in 381. He served as Praetorian prefect of both the Praetorian prefecture of Italy and the Praetorian prefecture of Illyricum, c. 382-383. An inscription of Gortyn, Crete praises him as the most illustrious of the consuls and praetorian prefects.
The Panegyric of Julian places her marriage to Constantius prior to the defeat of rival emperor Magnentius. Magnentius was dead by August 353. The marriage of Constantius and Eusebia may have occurred earlier in the year. "When he [Constantius] acquired the throne that had belonged to his ancestors, and had won it back from him [Magnentius] who had usurped it by violence and desired to wed that he might beget sons to inherit his honour and power, deemed this lady [Eusebia] worthy of his alliance, when he had already become of almost the whole world". In the original Medieval Greek text the word is "ecumene", a term originally used in the Greco-Roman world to refer to the inhabited Earth. Over time, the word came to mean the civilized world, and to be synonymous with the Roman Empire. The Prosopography interprets the text to mean that Constantius had yet to defeat Magnentius at the time.
The Panegyric mentions she asserted her influence early on. "Eusebia ... has come to be the partner of her husband's counsels, and though the Emperor is by nature merciful, good and wise, she encourages him to follow yet more becomingly his natural bent, and even turns justice to mercy. So that no one could even cite a case in which this Empress, whether with justice, as might happen, or unjustly, has ever been the cause of punishment or chastisement either great or small." ... "But not even when men richly deserve to suffer and be punished ought they to be utterly ruined. Now since the Empress recognises this, she has never bidden him [Constantius] inflict any injury of any kind, or any punishment or chastisement even on a single household of the citizens, much less on a whole kingdom or city. And I might add, with the utmost confidence that I am speaking the absolute truth, that in the case of no man or woman is possible to charge her with any misfortune that has happened, but all the benefits that she confers and has conferred, and on whom, I would gladly recount in as many cases as possible, and report them one by one, how for instance this man, thanks to her, enjoys his ancestral estate, and that man has been saved from punishment, though he was guilty in the eyes of the law, how a third escaped a malicious prosecution, though he came within an ace of the danger, how countless persons have received honour and office at her hands" 
Julian goes on to present Eusebia's patronage of her own family, alluding to practice of nepotism by the Empress. "When she had in the beginning secured her husband's good will for her actions like a "frontage shining from afar," to use the words of the great poet Pindar, she forthwith showered honours on all her family and kinsfolk, appointing to more important functions those who had already been tested and were of mature age, and making them seem fortunate and enviable, and she won for them the Emperor's friendship and laid the foundations of their present prosperity. And if anyone thinks, what is in fact true, that on their own account they are worthy of honour, he will applaud her all the more. For it is evident that it was their merit, far more than the ties of kinship, that she rewarded; and one could hardly pay her a higher compliment than that. Such then was her treatment of these. And to all who, since they were still obscure on account of their youth, needed recognition of any sort, she awarded lesser honours. And not only on her kinsfolk has she conferred such benefits, but whenever she learned that ties of friendship used to exist with her ancestors, she has not allowed it to be unprofitable to those who owned such ties, but she honours them, I understand, no less than her own kinsfolk, and to all whom she regard's [sic] as her father's friends she dispensed wonderful rewards for their friendship."
Julian mentions Eusebia visiting Rome in 354. Her husband was in Germania at the time. "The visit which she lately made to Rome when the Emperor was on his campaign and had crossed the Rhine by bridges or forts near the frontiers of Galetia ... I could indeed very properly have given an account of this visit, and described how the people and the Senate welcomed her with rejoicings and went to meet her with enthusiasm, and received her as is their custom to receive an Empress, and told the amount of the expenditure, how generous and splendid it was, and the costliness of the preparations, and reckoned up the sums she distributed to the presidents of the tribes and the centurions of the people."
Protection of Julian 
According to Julian, Eusebia was responsible of convincing Constantius to send him to Athens. There Julian continued his studies. Julian presents Constantius being kind to him since his infancy, "in return of which I ever showed myself loyal and faithful to him; but nevertheless of late I perceived that, I know not why, he was somewhat harsh towards me. Now the Empress no sooner heard a bare mention, not of any actual wrong-doing but of mere idle suspicion, than she deigned to investigate it, and before doing so would not admit or listen to any falsehood or unjust slander, but persisted in her request until she brought me into the Emperor's presence and procured me speech with him. And she rejoiced when I was acquitted of every unjust charge, and when I wished to return home, she first persuaded the Emperor to give her permission to give his permission and then furnished me with a safe escort. Then when some deity, the one I think who devised my former troubles, or perhaps cut short this journey, she sent me to visit Greece, having asked the favour on my behalf from the Emperor, when I had already left the country. This was because she had learned that I delighted in literature, and she knew that that place is the home of culture." 
This is also mentioned in Julian's "Letter To The Senate And People of Athens", The letter was written in 361 when Julian and his forces were marching east to face Constantius. Julian took the time to write a series of public letters which explained and justified his course of action. These letters were addressed to several cities of the empire which Julian was attempting to win over, including (at least) Athens, Corinth, Rome and Sparta. The letter to Athens happens to be the only one preserved to modern times. "As for me he [Constantius] reluctantly let me go, after dragging me hither and thither for seven whole months and keeping me under guard; so that had not some one of the gods desired that I should escape, and made the beautiful and virtuous Eusebia kindly disposed to me, I could not then have escaped from his hands myself".
Ammianus gives a more detailed account of the case, crediting her with saving Julian's life. He was suspected of treason following the execution of his half-brother Constantius Gallus in 354. "But then the artillery of slander was turned against Julian, the future famous emperor, lately brought to account, and he was involved, as was unjustly held, in a two-fold accusation: first, that he had moved from the estate of Macellum, situated in Cappadocia, into the province of Asia, in his desire for a liberal education; and, second, that he had visited his brother Gallus as he passed through Constantinople. And although he cleared himself of these implications and showed that he had done neither of these things without warrant, yet he would have perished at the instigation of the accursed crew of flatterers, had not, through the favour of divine power, Queen Eusebia befriended him; so he was brought to the town of Comum, near Milan, and after abiding there for a short time, he was allowed to go to Greece for the sake of perfecting his education, as he earnestly desired." 
Libanius confirms the story in his "Funeral Oration on Julian". "Against his brother Gallus there came a false accusation, and letters were discovered containing the blackest treachery; and when the culprits were punished for this (for he [Gallus] was not a likely person to reward them for it, after having been thus provoked), it was decided at Court that he who had inflicted punishment was guilty for what he had done——so he was destroyed in silence, the sword having anticipated his defence of his conduct. Upon this our hero [Julian] was arrested and kept a prisoner in the midst of armed men of fierce look and rough voice, and, by their actions, making imprisonment appear a trifle; to this was added his not being stationary in one place of confinement, but having to change one prison for another for the mere purpose of annoying him. And this treatment he suffered though no charge was brought against him, either small or great——for how could that be, because he had lived at a distance, from his brother, of more than three hundred posts? [The posts between Julian's residence in Nicomedia and Gallus' residence in Antioch. ] and even letters he only sent to his brother rarely, and those confined to mere compliments; in consequence of which no one came forward to accuse him, even falsely; but nevertheless, he was tormented, as I have said, for no other reason than because the two had one father. On this occasion again, he deserves to be admired for not having courted favour with the murderer [Constantius] by declarations against him that was dead, nor yet exasperating the living by speeches in defence of the same; but whilst he honoured the memory of the one [Gallus] by secret grief, he gave the other [Constantius] no occasion for a second murder, strongly as he desired it. So well and honourably did he bridle his own tongue, and this, too, though the annoyances that surrounded him rendered it no easy task; so that by his patience he gagged the mouths of the wickedest of men. Nevertheless, not even this would have sufficed for his preservation, nor have checked the malice of those enraged against him without a cause; but an "Ino daughter of Cadmus", looked down upon him, so tempest-tossed, in the person of the wife of Constantius [Eusebia]——the one [Julian] she pitied, the other [Constantius] she softened, and, by dint of many prayers, obtained his liberty, longing, as lie was, for Greek, and, above all, for that "Bye of Greece," Athens, to send him to the desired place." 
Socrates of Constantinople gives an almost identical account: "But when not long after this Gallus was slain, Julian was suspected by the emperor; wherefore he directed that a guard should be set over him: he soon, however, found means of escaping from them, and fleeing from place to place he managed to be in safety. At last the Empress Eusebia having discovered his retreat, persuaded the emperor to leave him uninjured, and permit him to go to Athens to pursue his philosophical studies."  Sozomen reports the same story: "When Gallus, his brother, who had been established as Cæsar, was put to death on being accused of revolution, Constantius also suspected Julian of cherishing the love of empire, and therefore put him under the custody of guards. Eusebia, the wife of Constantius, obtained for him permission to retire to Athens".
The reasons for Eusebia's sponsorship of Julian are unclear. Julian himself attributes this to her kindness (though this may include literary and political embellishment), while Ammianus Marcellinus offers more politically sophisticated motives. Modern historians Shaun Tougher and J. Juneau suggest that Eusebia's role may in fact have been part of Constantius's own strategy, using her as a "front woman" in negotiations with Julian, as the two men had a contentious relationship. Eusebia may have been able to help to build a valuable alliance where Constantius needed one.
Appointment of Julian as Caesar 
Narratives by Julian 
In 355, Eusebia supported the appointment of Julian as Caesar. Julian himself reports it in his Panegyric. "But Eusebia honored even the name. For no other reason can I discover, nor learn from anyone else, why she became so zealous an ally of mine, and an averter of evil and my preserver, and took such troubles and pain in order that I might retain unaltered and unaffected the Emperor's good will." ... "When a good opinion of me was established in the Emperor's mind, she rejoiced exceedingly, and echoed him harmoniously, bidding me take courage and neither refuse out of awe to accept the greatness of what was offered me [the title of Caesar], nor by employing a boorish and arrogant frankness, unworthily slight the urgent request of him who had shown such favour".
Julian gives further details in his letter to Athens. "He [Constantius] bade me retire for a short time to Greece, then summoned from there to the court again. He had never seen me before except once in Cappadoccia and once in Italy, -an interview which Eusebia had secured by her exertions so that I might feel confidence about my personal safety." ... "Now from the first moment of my arrival from Greece, Eusebia of blessed memory kept showing me the utmost kindness through the eunuchs of her household. And a little later when the Emperor returned ... at last I was given access to the court, and, in the words of the proverb, Thessalian persuasion was applied on me. For when I firmly declined all intercourse with the palace, some of them, as though they had come together in a barber's shop, cut off my beard and dressed me in a military cloak and transformed me into a highly ridiculous soldier, as they thought at the time. For none of the decorations of those villains suited me. And I walked not like them, staring about me and strutting along, but gazing on the ground as I had been trained to do by the preceptor [Mardonius] who brought me up. At the time then I inspired their ridicule, but a little later their suspicion, and then their jealousy was inflamed to the utmost".
"But this I must not omit to tell here, how I submitted and how I consented to dwell under the same roof with those whom I knew to have ruined my whole family, and who, I suspected, would before long plot against myself also. But floods of tears I shed and what laments I uttered when I was summoned, stretching out my hands to your Acropolis and imploring Athene to save her suppliant and not to abandon me, many of you who were eyewitnesses can attest, and the goddess herself, above all others, is my witness that I even begged for death at her hands there in Athens rather than my journey to the Emperor. That the goddess accordingly did not betray her suppliant or abandoned him she proved by the event. For everywhere she was my guide, and on all sides she set a watch near me, bringing guardian angel from Helios and Selene. What happened was somewhat as follows. When I came to Milan I resided in one of the suburbs. Thither Eusebia sent me on several occasions messages of good-will, and urged me to write to her without hesitation about anything that I desired. Accordingly I wrote her a letter, or rather a petition containing vows like these: "May you have children to succeed you; may God grant you this and that, if only you send me home as quickly as possible!" But I suspected it was not safe to send to the palace letters addressed to the Emperor's wife. Therefore I besought the gods to inform me at night whether I ought to send the letter to the Empress. And they warned me that if I sent it I should meet the most ignominious death. I call all the gods to witness that what I write here is true. For this reason, therefore, I forbore to send the letter.
"The slavery that ensued and the fear for my very life that hung over me every day, Heracles, how great it was, and how terrible! My doors locked, warders to guard them, the hands of my servants searched lest one of them should convey to me the most trifling letter from my friends, strange servants to wait on me! Only with difficulty was I able to bring with me to court four of my own domestics for my personal service, two of them mere boys and two older men, of whom only one knew of my attitude to the gods, and, as far as he was able, secretly joined me in their worship. I had entrusted with the care of my books, since he was the only one with me of many loyal comrades and friends, a certain physician who had been allowed to leave home with me because it was not known that he was my friend." The physician is identified as Oribasius in the private correspondence of Julian. "And this state of things caused me such alarm and I was so apprehensive about it, that though many of my friends really wished to visit me, I very reluctantly refused them admittance; for though I was most anxious to see them, I shrank from bringing disaster upon them and myself at the same time.
"For to rush headlong into unseemly and foreseen danger while trying to avoid future plots seemed to me a topsy-turvy proceeded. Accordingly I consented to yield. And immediately I was invested with the title and robe of Caesar. ... "Constantius gave me three hundred and sixty soldiers, and in the middle of the winter dispatched me to Gaul, which was then in a state of great disorder; and I was sent not as commander of the garrisons there but rather as a subordinate of the generals there stationed. For letters had been sent them and express orders given that they were to watch me as vigilantly as they did the enemy, for fear I should attempt to cause a revolt.
Narrative by Ammianus Marcellinus 
While Julian focuses on his dread of Constantius' intentions towards him, Ammianus reports on the situation in the palace leading to Julian's appointment. Giving more details on the motivations of Constantius and Eusebia. "Constantius was disquieted by frequent messages reporting that Gaul was in desperate case, since the savages were ruinously devastating everything without opposition. And after worrying for a long time how he might forcibly avert these disasters, while himself remaining in Italy as he desired — for he thought it risky to thrust himself into a far-distant region — he at length hit upon the right plan and thought of associating with himself in a share of the empire his cousin Julian, who not so very long before had been summoned from the district of Achaia and still wore his student's cloak."
"When Constantius, driven by the weight of impending calamities, admitted his purpose to his intimates, openly declaring (what he had never done before) that in his lone state he was giving way before so many and such frequent crises, they, being trained to excessive flattery, tried to cajole him, constantly repeating that there was nothing so difficult that his surpassing ability and a good fortune so nearly celestial could not overcome as usual. And several, since the consciousness of their offences [against Julian] pricked them on, added that the title of Caesar ought henceforth to be avoided, rehearsing what had happened under Gallus. To them in their obstinate resistance the queen [Eusebia] alone opposed herself, whether she dreaded journeying to a far country or with her native intelligence took counsel for the common good, and she declared that a kinsman ought to be preferred to every one else. So, after much bandying the matter to and fro in fruitless deliberations, the emperor's resolution stood firm, and setting aside all bootless discussion, he decided to admit Julian to a share in the imperial power. So when he had been summoned and had arrived, on an appointed day all his fellow-soldiers there present were called together, and a platform was erected on a lofty scaffolding, surrounded by the eagles and the standards. On this Augustus stood, and holding Julian by the right hand, in a quiet tone delivered the following address:" 
"We stand before you, valiant defenders of our country, to avenge the common cause with one all but unanimous spirit; and how I shall accomplish this I shall briefly explain to you, as impartial judges. After the death of those rebellious tyrants whom mad fury drove to attempt the designs which they projected, the savages, as if sacrificing to their wicked Manes with Roman blood, have forced our peaceful frontier and are over-running Gaul, encouraged by the belief that dire straits beset us throughout our far-flung empire. If this evil therefore, which is already creeping on beyond set bounds, is met by the accord of our and your wills while time permits, the necks of these proud tribes will not swell so high, and the frontiers of our empire will remain inviolate. It remains for you to confirm with happy issue the hope of the future which I cherish. This Julian, my cousin as you know, rightly honoured for the modesty through which he is as dear to us as through ties of blood, a young man of ability which is already conspicuous, I desire to admit to the rank of Caesar, and that this project, if it seems advantageous, may be confirmed also by your assent." 
"As he was attempting to say more to this effect, the assembly interrupted and gently prevented him, declaring as if with foreknowledge of the future that this was the will of the supreme divinity rather than of any human mind. And the emperor, standing motionless until they became silent, went on with the rest of his speech with greater assurance: "Since, then," said he, "your joyful acclaim shows that I have your approval also, let this young man of quiet strength, whose temperate behaviour is rather to be imitated than proclaimed, rise to receive this honour conferred upon him by God's favour. His excellent disposition, trained in all good arts, I seem to have fully described by the very fact that I have chosen him. Therefore with the immediate favour of the God of Heaven I will invest him with the imperial robes." This he said and then, after having clothed Julian in the ancestral purple and proclaimed him Caesar to the joy of the army, he thus addressed him, somewhat melancholy in aspect as he was, and with careworn countenance":
"My brother, dearest to me of all men, you have received in your prime the glorious flower of your origin; with increase of my own glory, I admit, since I seem to myself more truly great in bestowing almost equal power on a noble prince who is my kinsman, than through that power itself. Come, then, to share in pains and perils, and undertake the charge of defending Gaul, ready to relieve the afflicted regions with every bounty. And if it becomes necessary to engage with the enemy, take your place with sure footing amid the standard bearers themselves; be a thoughtful advisor of daring in due season, animate the warriors by taking the lead with utmost caution, strengthen them when in disorder with reinforcements, modestly rebuke the slothful, and be present as a most faithful witness at the side of the strong, as well as of the weak. Therefore, urged by the great crisis, go forth, yourself a brave man, ready to lead men equally brave. We shall stand by each other in turn with firm and steadfast affection, we shall campaign at the same time, and together we shall rule over a pacified world, provided only God grants our prayers, with equal moderation and conscientiousness. You will seem to be present with me everywhere, and I shall not fail you in whatever you undertake. In fine, go, hasten, with the united prayers of all, to defend with sleepless care the post assigned you, as it were, by your country herself." 
"After this address was ended, no one held his peace, but all the soldiers with fearful din struck their shields against their knees (this is a sign of complete approval; for when, on the contrary, they smite their shields with their spears it is an indication of anger and resentment), and it was wonderful with what great joy all but a few approved Augustus' choice and with due admiration welcomed the Caesar, brilliant with the gleam of the imperial purple. Gazing long and earnestly on his eyes, at once terrible and full of charm, and on his face attractive in its unusual animation, they divined what manner of man he would be, as if they had perused those ancient books, the reading of which discloses from bodily signs the inward qualities of the soul. And that he might be regarded with the greater respect, they neither praised him beyond measure nor less than was fitting, and therefore their words were esteemed as those of censors, not of soldiers. Finally, he was taken up to sit with the emperor in his carriage and conducted to the palace, whispering this verse from the Homeric song: "By purple death I'm seized and fate supreme."" The verse was derived by the Iliad of Homer. In particular a scene of its fifth book: "And Eurypylus, son of Euaemon, slew goodly Hypsenor, son of Dolopion high of heart, that was made priest of Scamander, and was honoured of the folk even as a god —upon him did Eurypylus, Euaemon's glorious son, rush with his sword as he fled before him, and in mid-course smite him upon the shoulder and lop off his heavy arm. So the arm all bloody fell to the ground; and down over his eyes came dark death and mighty fate."  The word play derives from the Greek language word "porphyra" (or porphura, πορφύρα) for the purple-red dye of the imperial robes. In the Iliad the word signifies "dark red, purple or crimson", the color of blood in the various scenes of death in battle. "This happened on the sixth of November of the year when Arbetio and Lollianus were consuls.  Then, within a few days, Helena, the maiden sister of Constantius, was joined in the bonds of wedlock to the Caesar; and when everything had been prepared which the imminence of his departure demanded, taking a small suite, he set out on the first of December, escorted by Augustus as far as the spot marked by two columns, lying between Laumello and Pavia, and came by direct marches to Turin." 
Narrative by Zosimus 
The role of Eusebia in the appointment is also mentioned by Zosimus. Constantius "perceiving all the Roman territories to be infested by the incursions of the Barbarians, and that the Franks, the Alemanni, and the Saxons had not only possessed themselves of forty cities near the Rhine, but had likewise ruined and destroyed them, by carrying off an immense number of the inhabitants, and a proportionate quantity of spoils; and that the Sarmatians and the Quadi ravaged without opposition Pannonia and the upper Moesia ; besides which that the Persians were perpetually harassing the eastern provinces, though they had previously been tranquil in the fear of an attack from Gallus Caesar. Considering these circumstances, and being in doubt what to attempt, he scarcely thought himself capable of managing affairs at this critical period. He was unwilling, however, to associate any one with himself in the government, because he so much desired to rule alone, and could esteem no man his friend. Under these circumstances he was at a loss how to act. It happened, however, that when the empire was in the greatest danger, Eusebia, the wife of Constantius, who was a woman of extraordinary learning, and of greater wisdom than her sex is usually endowed with, advised him to confer the government of the nations beyond the Alps on Julianus Caesar, who was brother to Gallus, and grandson to Constantius. As she knew that the emperor was suspicious of all his kindred, she thus circumvented him. She observed to him, that Julian was a young man unacquainted with the intrigues of state, having devoted himself totally to his studies; and that he was wholly inexperienced in worldly business. That on this account he would be more fit for his purpose than any other person. That either he would be fortunate, and his success would be attributed to the emperor's conduct, or that he would fail and perish; and that thus Constantius would have none of the imperial family to succeed to him." 
"Constantius, having approved her advice, sent for Julian from Athens, where he lived among the philosophers, and excelled all his masters in every kind of learning. Accordingly, Julian returning from Greece into Italy, Constantius declared him Caesar, gave him in marriage his sister Helena, and sent him beyond the Alps. But being naturally distrustful, he could not believe that Julian would be faithful to him, and therefore sent along with him Marcellus and Sallustius, to whom, and not to Caesar, he committed the entire administration of that government." 
Second visit to Rome 
In 357, Constantius and Eusebia visited Rome, her second recorded visit to the city. "The Cambridge Ancient History" notes that the occasion of her presence in Rome were the Vicennalia of Constantius II, a celebration in honor of completing twenty years on the throne. Constantius and his Milan court moved to Rome for the occasion, marking the first and only known visit of this particular Augustus in the ancient capital of the Roman Empire. Constantius was following the examples of Diocletian and Constantine I who also visited Rome during their own Vicennalia. The presence of Constantius, Eusebia and Helena marked this as a dynastic display.
Ammianus narrates: "In the second prefecture of Orfitus he passed through Ocriculi [actually, Otricoli on the Via Flaminia, the road leading to Rome], elated with his great honours and escorted by formidable troops; he was conducted, so as to speak, in battle array and everyone's eyes were riveted upon him with fixed gaze. And when he was nearing the city, as he beheld with calm countenance the dutiful attendance of the senate and the august likenesses of the patrician stock, he thought, not like Cineas, the famous envoy of Pyrrhus, that a throng of kings was assembled together, but that the sanctuary of the whole world was present before him. And when he turned from them to the populace, he was amazed to see in what crowds men of every type had flocked from all quarters to Rome. And as if he were planning to overawe the Euphrates with a show of arms, or the Rhine, while the standards preceded him on each side, he himself sat alone upon a golden car in the resplendent blaze of shimmering precious stones, whose mingled glitter seemed to form a sort of shifting light. And behind the manifold others that preceded him he was surrounded by dragons, woven out of purple thread and bound to the golden and jewelled tops of spears, with wide mouths open to the breeze and hence hissing as if roused by anger, and leaving their tails winding in the wind. And there marched on either side twin lines of infantrymen with shields and crests gleaming with glittering rays, clad in shining mail; and scattered among them were the full-armoured cavalry (whom they called clibanarii), all masked, furnished with protecting breastplates and girt with iron belts, so that you might have supposed them statues polished by the hand of Praxiteles, not men. Thin circles of iron plates, fitted to the curves of their bodies, completely covered their limbs; so that whichever way they had to move their members, their garment fitted, so skilfully were the joinings made. Accordingly, being saluted as Augustus with favouring shouts, while hills and shores thundered out the roar, he never stirred, but showed himself as calm and imperturbable as he was commonly seen in his provinces. For he both stooped when passing through lofty gates (although he was very short), and as if his neck were in a vice, he kept the gaze of his eyes straight ahead, and turned his face neither to right nor to left, but (as if he were a lay figure) neither did he nod when the wheel jolted nor was he ever seen to spit, or to wipe or rub his face or nose, or move his hands about. And although this was affectation on his part, yet these and various other features of his more intimate life were tokens of no slight endurance, granted to him alone, as was given to be understood." 
"So then he entered Rome, the home of empire and of every virtue, and when he had come to the Rostra, the most renowned forum of ancient dominion, he stood amazed; and on every side on which his eyes rested he was dazzled by the array of marvellous sights. He addressed the nobles in the senate-house and the populace from the tribunal, and being welcomed to the place with manifold attentions, he enjoyed a longed-for pleasure; and on several occasions, when holding equestrian games, he took delight in the sallies of the commons, who were neither presumptuous nor regardless of their old-time freedom, while he himself also respectfully observed the due mean. For he did not (as in the case of other cities) permit the contests to be terminated at his own discretion, but left them (as the custom is) to various chances. Then, as he surveyed the sections of the city and its suburbs, lying within the summits of the seven hills, along their slopes, or on level ground, he thought that whatever first met his gaze towered above all the rest: the sanctuaries of Tarpeian Jove so far surpassing as things divine excel those of earth; the baths built up to the measure of provinces; the huge bulk of the amphitheatre, strengthened by its framework of Tiburtine stone, to whose top human eyesight barely ascends; the Pantheon like a rounded city-district, vaulted over in lofty beauty; and the exalted heights which rise with platforms to which one may mount, and bear the likenesses of former emperors; the Temple of the City, the Forum of Peace, the Theatre of Pompey,the Odeum, the Stadium, and amongst these the other adornments of the Eternal City. But when he came to the Forum of Trajan, a construction unique under the heavens, as we believe, and admirable even in the unanimous opinion of the gods, he stood fast in amazement, turning his attention to the gigantic complex about him, beggaring description and never again to be imitated by mortal men. Therefore abandoning all hope of attempting anything like it, he said that he would and could copy Trajan's steed alone, which stands in the centre of the vestibule, carrying the emperor himself. To this prince Ormisda, who was standing near him, and whose departure from Persia I have described above, replied with native wit: "First, Sire," said he, "command a like stable to be built, if you can; let the steed which you propose to create range as widely as this which we see." When Ormisda was asked directly what he thought of Rome, he said that he took comfort in this fact alone, that he had learned that even there men were mortal. So then, when the emperor had viewed many objects with awe and amazement, he complained of Fame as either incapable or spiteful, because while always exaggerating everything, in describing what there is in Rome, she becomes shabby. And after long deliberation what he should do there, he determined to add to the adornments of the city by erecting in the Circus Maximus an obelisk, the provenance and figure of which I shall describe in the proper place." 
"Now the emperor desired to remain longer in this most majestic abode of all the world, to enjoy freer repose and pleasure, but he was alarmed by constant trustworthy reports, stating that the Suebi were raiding Raetia and the Quadi Valeria while the Sarmatians, a tribe most accomplished in brigandage, were laying waste Upper Moesia and Lower Pannonia. Excited by this news, on the thirtieth day after entering Rome he left the city on May 29, and marched rapidly into Illyricum by way of Tridentum.
Poisoning of Helena 
Her presence in the following visit is mentioned by Ammianus in another part of the above chapter, in connection to the miscarriages of Helena: "Meanwhile Constantius' sister Helena, wife of Julian Caesar, had been brought to Rome under pretence of affection, but the reigning queen, Eusebia, was plotting against her; she herself had been childless all her life, and by her wiles she coaxed Helena to drink a rare potion, so that as often as she was with child she should have a miscarriage. For once before, in Gaul, when she had borne a baby boy, she lost it through machination: a midwife had been bribed with a sum of money, and as soon as the child was born cut the umbilical cord more than was right, and so killed it; such great pains and so much thought were taken that this most valiant man might have no heir."  In the historical study "Ammianus Marcellinus and the Representation of Historical Reality" (1998) by Timothy Barnes, the birth of this stillborn son is estimated to 356. The miscarriage in Rome to 357. Barnes considers the story of the potion-induced miscarriages to be an allegation without further reference. Edward Gibbon had not completely dismissed the report:"even the fruits of his [Julian's] marriage-bed were blasted by the jealous artifices of Eusebia herself, who, on this occasion alone, seems to have been unmindful of the tenderness of her sex, and the generosity of her character" ... "For my own part I am inclined to hope that the public malignity imputed the effects of accident as the guilt of Eusebia." He left the question of the existence of such a poison open and to be determined by physicians rather than historians. "A History of Medicine" (1995) by Plinio Prioreschi dismisses the account as an example of a very common error in accounts of ancient medicine, "the attribution to drugs of properties that they could not have". In this case, a potion which is consumed just once and keeps having effect for years. Prioreschi regards it as "an obvious impossibility in the light of modern pharmacology".
"The Propaganda of Power: The Role of Panegyric in Late Antiquity" (1998) contains a number of essays on the subject of panegyrics. Among them is "In praise of an Empress:Julian's speech of thanks to Eusebia" by Shaun Tougher, discussing a "Panegyric In Honour Of Eusebia" written by Julian himself. Tougher examines the relationship of Julian and Eusebia, commenting on whether Helena was affected by it. The historian considers that the image of a politically influential but "kind-hearted and philanthropic" Eusebia is directly based on her depiction in the works of Julian. According to Tougher, later historians have tended to accept this depictions with little to no questioning of it. He regards Eusebia to be the greatest threat to Julian for the duration of his term as Caesar. This rank effectively made Julian heir presumptive to the imperial throne. His position as such relied solely on Constantius and Eusebia remaining childless. Had an heir been born to the imperial couple, Julian could find himself outliving his usefulness to his imperial patrons. Tougher follows the example of senior historian Noël Aujoulat in considering the story of Helena's miscarriages being the result of abortifacients to be entirely plausible. Both historians consider Ammianus' allegations, casting Eusebia as the orchestrator of such a plot, should be taken into consideration and "not be lightly dismissed".
Ambitions of Barbatio 
Eusebia is mentioned again in 359, when Barbatio and his wife Assyria were executed for supposedly harboring imperial ambitions. According to Ammianus Assyria feared that her husband wanted to replace Constantius both as Emperor and as Eusebia's husband. The account of the affair has as following: "Barbatio had a wife, Assyria by name, who was talkative and indiscreet. She, when her husband had gone forth on a campaign and was worried by many fears because of what he remembered had been foretold him, overcome by a woman's folly, confided in a maidservant skilled in cryptic writing, whom she had acquired from the estate of Silvanus. Through her Assyria wrote at this untimely moment to her husband, entreating him in tearful accents that when, after Constantius' approaching death, he himself had become emperor, as he hoped, he should not cast her off and prefer marriage with Eusebia, who was then queen and was conspicuous among many women for the beauty of her person. After this letter had been sent with all possible secrecy, the maidservant, who had written it at her mistress' dictation, as soon as all had returned from the campaign took a copy of it and ran off to Arbetio in the quiet of the night; and being eagerly received, she handed over the note. Arbetio, who was of all men most clever in framing an accusation, trusting to this evidence reported the matter to the emperor. The affair was investigated, as usual, without delay or rest, and when Barbatio admitted that he had received the letter, and strong evidence proved that the woman had written it, both were beheaded." 
As pointed by R. Haston Norwood in his assessment of Barbatio, the letter was not composed by Assyria herself, but by a female slave, who had formerly belonged to Silvanus, and may possibly have harboured some grudge towards her new owners. The servant immediately took a copy of this letter to Arbitio, suggesting that the whole thing was part of an elaborate plot. There is no evidence at all that Barbatio actually planned to murder Constantius. According to some historians, it seems more likely that, following his usual pattern of behaviour, he simply wished to ingratiate himself still further with the Emperor, with the possible hope of becoming a co-Augustus. It is also questionable if the incriminating letter contained Assyria's actual words.
Role in religion 
Eusebia exerted considerable influence on the emperor and affected political decisions in the court. She used her influence to promote the doctrine of Arianism and the rise of Julian, who succeeded Constantius II as emperor. Eusebia is often noted for her wisdom and kindness, as well as her loyalty to Constantius. It has been suggested that Constantius honored her loyalty by renaming the Dioecesis Pontica as Pietas, the Latin equivalent of her Greek name; both the Greek and Roman words refer to piety as well as family loyalty, including the loyalty of a wife to her husband. The information about the diocese named in her honor comes from Ammianus. On 24 August 358, a major earthquake destroyed Nicomedia. Among the victims, Ammianus names "Aristaenetus, vice-governor of the recently created diocese which Constantius, in honour of his wife, Eusebia, had named Pietas; by this kind of mishap he slowly panted out his life amid torments."  The Epitome de Caesaribus, attributed to Aurelius Victor, mentions Constantius' own devotion to Eusebia. Constantius "was addicted to the love of eunuchs, courtiers, and wives, by whom - satisfied by no deviant or unlawful pleasure - he used to be polluted. But from wives, many whom he obtained, he especially delighted in Eusebia, who was indeed elegant, but, through Adamantiae and Gorgoniae and other dangerous abettors, harmful of her husband's reputation, contrary to what is customary for more upright females whose precepts often aid their husbands." 
Her role as an Arian is noted by Sozomen. "We have now seen what events transpired in the churches during the reign of Constantine. On his death the doctrine which had been set forth at Nicaea, was subjected to renewed examination. Although this doctrine was not universally approved, no one, during the life of Constantine, had dared to reject it openly. At his death, however, many renounced this opinion, especially those who had previously been suspected of treachery. Of all these Eusebius and Theognis, bishops of the province of Bithynia, did everything in their power to give predominance to the tenets of Arius. They believed that this object would be easily accomplished, if the return of Athanasius from exile could be prevented, and by giving the government of the Egyptian churches to a bishop of like opinion with them. They found an efficient coadjutor in the presbyter who had obtained from Constantine the recall of Arius. He was held in high esteem by the emperor Constantius, on account of the service he had rendered in delivering to him the testament of his father; since he was trusted, he boldly seized the opportunities, until he became an intimate of the emperor’s wife, and of the powerful eunuchs of the women’s sleeping apartments. At this period Eusebius [Eusebius the eunuch, chief chamberlain] was appointed to superintend the concerns of the royal household, and being zealously attached to Arianism, he induced the empress and many of the persons belonging to the court to adopt the same sentiments. Hence disputations concerning doctrines again became prevalent, both in private and in public, and revilings and animosities were renewed. This state of things was in accordance with the views of Theognis and his partisans." 
Theodoret records that Eusebia send money to the exiled Pope Liberius in 355. "After the lapse of two days the emperor sent for Liberius, and finding his opinions unchanged, he commanded him to be banished to Beroea, a city of Thrace. Upon the departure of Liberius, the emperor sent him five hundred pieces of gold to defray his expenses. Liberius said to the messenger who brought them, “Go, and give them back to the emperor; he has need of them to pay his troops.” The empress also sent him a sum of the same amount; he said, “Take it to the emperor, for he may want it to pay his troops; but if not, let it be given to Auxentius and Epictetus, for they stand in need of it.” Eusebius the eunuch brought him other sums of money, and he thus addressed him: “You have turned all the churches of the world into a desert, and do you bring alms to me, as to a criminal? Begone, and become first a Christian." He was sent into exile three days afterwards, without having accepted anything that was offered him." 
The Suda gives an account of Eusebia's apparent conflict with Leontius, bishop of Tripolis, Lydia on the latter's entry. "Once when a council was held, and Eusebia the wife of Constantius was puffed up by a swelling of self-esteem and treated with reverence by the bishops, he alone stayed at home treating her with indifference. But she feeling overheated in her passions and inflamed in her sentiment, sent to him, begging and flattering him with promises, [saying], “I will build a very great church for you and will spend a lot of money on it, if you come to me.” But he replied, “If you wish to accomplish any of this, O empress, know that you will not benefit me more than your own soul. But if you wish me to come to you, so that the respect due to bishops may be preserved, let me come to you, but do you descend at once from your lofty throne and meet me and offer your head to my hands, asking for my blessing. And then let me sit down, but do you stand respectfully, and sit only when I bid you, when I give the signal. If you accept this, I would come to you; but in any other way, you cannot give so much nor be capable of such great deeds that we, neglecting the honor due to the bishops, would do violence to the divine order of priesthood.” When this message was reported to her, she swelled up in her soul, not considering it endurable to accept such words from Leontios. Swelling with great anger and filled with emotion and making many threats from a woman’s passionate and shallow disposition and describing [the situation] to her husband, she urged him to vengeance. But he instead praised the independence of [Leontios'] judgment and rebuked his wife for her anger and sent her away to the women’s quarters." 
Like Constantius' first wife (whose name is unknown), Eusebia tried unsuccessfully to give birth to a child. It was said that Eusebia embraced Arianism when the efforts of the orthodox bishops to cure her infertility failed. The ancient historian Philostorgius wrote that the Arian bishop and renowned healer Theophilus the Indian was called out of exile to heal her troubled womb. He is said to have healed her malady, but she still bore no children. Eusebia is reported to have died while in the care of a female practitioner who attempted to restore her fertility.
According to his modern translator and commentator, Philip R. Amidon, Philostorgius "says that Constantius' wife was subject to fits of hysteria, and since he was so deeply devoted to her, he was forced to recall Theophilus from exile, for the latter was reputed to be able to cure sicknesses by divine power. When he arrived, he asked forgiveness for the sins he had committed against him and besought him to cure his wife. Nor did he fail of his request, so our author says. For Theophilus laid his propriatory hands upon the woman and removed the sickness from her". Amidon notes that Eusebia's hysteria is also mentioned by Georgios Kedrenos and Joannes Zonaras.
Constantius married his next wife, Faustina after the death of Eusebia in 360. The period can be estimated by Ammianus who reports that this marriage took place while Constantius was wintering in Antioch, taking a break from the ongoing Roman–Persian Wars. "At that same time Constantius took to wife Faustina, having long since lost Eusebia".
Modern historians 
Shaun Tougher notes that the panegyric in honor of Eusebia "tends to be neglected" in favor of two orations Julian wrote about Constantius II. Tougher also notes a tendency to take this text "at face value" instead of receiving "deeper analysis". He offers an analysis on how the oration was influenced by first the praise of Arete as found in the Odyssey by Homer, secondly the treatises on speeches of Menander of Laodicea. Menander advised that the praise on an emperor's virtue should focus on four areas: his courage, justice, temperance and wisdom. Julian manages to praise the justice, temperance and wisdom of Eusebia. Notably missing is any reference to her courage. However there are additional references to her mildness, clemency, philanthropy and liberality.
Tougher notes that Julian reveals her influence on the decisions of Constantius. But constantly reminds his audience that the authority to decide on any given matter rests with the Emperor, not with the Empress. She persuades but does not command. The historian notes how Julian manages to stray from his titular subject and to offer readers a quite detailed portrait of himself, far more detailed than the one on Eusebia. His self-portrayal covers so much of the oration that in Tougher's words "the rhetorician is in danger of eclipsing his subject.
On the matter of portrayal two key elements are the benevolent portrayal of Eusebia and his "satisfaction" at being sent to Athens. Tougher invites the aspiring historian to be cautious on either one. He notes that the oration manages to incorporate both "implied and direct criticism" of the imperial couple. This is only the version of events presented by Julian. A version that might have managed to influence Ammianus Marcellinus and through him later historians. Julian has shaped the historical narrative and portrayal of much of his life. The luck of other perspectives questions its reliability.
"Ammianus Marcellinus and the Representation of Historical Reality" (1998) by Timothy Barnes focuses on the elements shaping Ammianus' account. He notes that "Just as with the male characters in his history ... Ammianus reveals his personal likes and dislikes without inhibition when dealing with the wives of Emprerors". Barnes notes that his portrayal of Eusebia was mostly positive but his motives may be clearly identified. Eusebia's role as "protector of Julian" and sister of Hypatius would require such positive treatment. The historian cleary portrays Julian as a hero and his allies are cast in a favorable light by association. Ammianus has only warm praise for Hypatius, pointing to the latter being his friend and a probable patron. Even Ammianus' settlement in Rome matches the period when Hypatius was its prefect. Suggesting Ammianus had either arrived in the city with his friend or followed him there at a later date. Thus high praise to the sister of Hypatius.
"A History of Women in the West: From Ancient Goddesses to Christian Saints" (1994) was a historical study of the role and depiction of women in the Western world, presenting articles by several historians. They relate the manner of Eusebia's death to the "fear of sterility" in Ancient Roman society. The purpose of marriage in ancient Rome was very specific, reproduction. "Women who wished to be released from guardianship were required to produce three or four children (three for a freeborn woman, four for freedwomen." The laws of Augustus (reigned 27 BC-14 AD) prevented unmarried, widowed and divorced women from receiving inheritance. Social expectations required women to be married and with children by their twentieth year. Widows and divorced women were expected to remarry within at least one year of the time they became "unmarried" again. Men were also subject to laws preventing them to inherit until having a certain number of children. Sterile couples could lose the rights to much of their respective inheritance in favor of relatives or even the state. So there would be indeed much pressure for children. When children were "slow in coming", the women would turn to religion or take drugs to counter their infertility. The fate of Eusebia would point that the fertility medication available to them were no less dangerous than their abortifacients.
Daughter of Julius Constantius
|Roman Empress consort
with Helena (360)
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- q:Macedonia (region)
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