Tyrannius Rufinus or Rufinus of Aquileia (Rufinus Aquileiensis; 340/345 – 410) was a monk, historian, and theologian. He is most known as a translator of Greek patristic material into Latin—especially the work of Origen.
Rufinus was born in 344 or 345 in the Roman city of Julia Concordia (now Concordia Sagittaria), near Aquileia (in modern-day Italy) at the head of the Adriatic Sea. It appears that both of his parents were Christians.
Around 370, he was living in a monastic community in Aquileia when he met Jerome. In about 372, Rufinus travelled to the eastern Mediterranean, where he studied in Alexandria under Didymus the Blind for some time, and also cultivated friendly relations with Macarius the elder and other ascetics in the desert. In Egypt, if not even before leaving Italy, he had become intimately acquainted with Melania the Elder, a wealthy and devout Roman widow. When she removed to Palestine, taking with her a number of clergy and monks on whom the persecutions of the Arian Valens had borne heavily, Rufinus followed her, moving to Jerusalem in 380. There, while his patroness lived in a convent of her own in Jerusalem, Rufinus, at her expense, gathered together a number of monks to form a new monastery on the Mount of Olives, devoting himself at the same time to the study of Greek theology. This combination of the contemplative life and the life of learning had already developed in the Egyptian monasteries. When Jerome came to Bethlehem in 386, the friendship formed at Aquileia was renewed. Jerome, along with his patroness Paula, set up a similar community in Bethlehem a few years later. Another of the intimates of Rufinus was John, bishop of Jerusalem, and formerly a Nitrian monk, by whom he was ordained to the priesthood in 390.
In 394, in consequence of the attack upon the doctrines of Origen made by Epiphanius of Salamis during a visit to Jerusalem, a fierce quarrel broke out, which found Rufinus and Jerome on different sides. Although both Jerome and Rufinus had previously been great admirers of Origen's work, in the light of Epiphanius's criticism of Origen, Jerome felt that Rufinus was not fierce enough in attacking the works of Origen. Three years afterwards a formal reconciliation was brought about between Jerome and John, but this was to prove only temporary.
In the autumn of 397 Rufinus embarked for Rome, where, finding that the theological controversies of the East were exciting much interest and curiosity, he published a Latin translation of the Apology of Pamphilus for Origen, and also (398-99) a somewhat free rendering of the Περι Αρχων (or De Principiis) of that author himself. In the preface to the latter work he referred to Jerome as an admirer of Origen, and as having already translated some of his works with modifications of ambiguous doctrinal expressions. This allusion annoyed Jerome, who was exceedingly sensitive as to his reputation for orthodoxy, and the consequence was a bitter pamphlet war, with Rufinus' Against Jerome and Jerome's Against Rufinus. Such works are very wonderful to the modern onlooker, who finds it difficult to see anything discreditable in the accusation against a biblical scholar that he had once thought well of Origen, or in the counter-charge against a translator that he had avowedly exercised editorial functions as well.
At the instigation of Theophilus of Alexandria, Pope Anastasius I (399-401) summoned Rufinus from Aquileia to Rome to vindicate his orthodoxy; but he excused himself from a personal attendance in a written Apologia pro fide sua. The pope in his reply expressly condemned Origen, but left the question of Rufinus's orthodoxy to his own conscience. He was, however, regarded with suspicion in orthodox circles (cf. the Decretum Gelasii, 20) in spite of his services to Christian literature.
Rufinus spent most of the first decade of the fifth century translating Origen. He translated Origen's homilies for the whole Heptateuch except Deuteronomy, and others on selected Psalms, the Song of Songs, and 1 Samuel. Rufinus' translation of Origen's Commentary on Romans (c405-6) gave fresh stimulus to discussions of destiny and free will that had been going on in Roman circles since the mid-390s and would shortly come to an issue in Augustine's clash with Pelagius.
Rufinus also translated other works. These include Eusebius' Ecclesiastical History, translated in 401 at the request of Bishop Chromatius of Aquileia as an antidote to the terror caused by the Gothic incursions into Italy. Rufinus omits much of Eusebius' tenth book, and compresses what remains of it into book 9; he also retouches the narrative in several places and adds two books of his own to bring the account down to the death of Theodosius the Great (395).
Such translations often appear to have been done to commission, or with a local readership in mind, and so it seems likely that Rufinus worked with the support of friends and patrons. Between 397 and 408 he was resident in Italy, probably mainly in Rome and Aquileia; in 408 we find Rufinus at the monastery of Pinetum (in the Campagna?), having been driven there by the arrival of Alaric to Sicily, being accompanied by Melania in his flight. He died in Sicily in 411.
Original Works 
- Commentarius in symbolum apostolorum: a commentary on the Apostles' Creed which gives evidence of its use and interpretation in 4th-century Italy. (Commentary on the Apostles' Creed, at New Advent)
- The Church History of Rufinus of Aquileia.
Many of his extant works are defenses of himself against attacks by Jerome.
- De Adulteratione Librorum Origenis – an appendix to his translation of the Apology of Pamphilus, and intended to show that many of the features in Origen's teaching which were then held to be objectionable arise from interpolations and falsifications of the genuine text
- De Benedictionibus XII Patriarcharum Libri II – an exposition of Gen. xlix.
- Apologia s. Invectivarum in Hieronymum Libri II
- Apologia pro Fide Sua ad Anastasium Pontificem (Apology, Sent to Anastasius, Bishop of the City of Rome, at New Advent)
- Historia Eremitica – consisting of the lives of thirty-three monks of the Nitrian desert
Translations from Greek to Latin 
Origen's commentary on the New Testament Epistle to the Romans, along with many of his sermons on the Old Testament, survive only in versions by Rufinus. The full text of Origen's De principiis (On first principals) also survives only in Rufinus's translation. Jerome, earlier a friend of Rufinus, fell out with him and wrote at least three works opposing his opinions and condemning his translations as flawed. For instance, Jerome prepared a (now lost) translation of Origen's De principiis to replace Rufinus's translation, which Jerome said was too free.
The other translations of Rufinus are
- the Instituta Monachorum and some of the Homilies of Basil of Caesarea
- the Apology of Pamphilus, referred to above
- Origen's Principia
- Origen's Homilies (Gen. Lev. Num. Josh. Kings, also Cant, and Rom.)
- Opuscula of Gregory of Nazianzus
- the Sententiae of Sixtus, an unknown Greek philosopher
- the Sententiae of Evagrius
- the Clementine Recognitions (the only form in which that work is now extant)
- the Canon Paschalis of Anatolius Alexandrinus.
We can hardly overestimate the influence which Rufinus exerted on Western theologians by thus putting the great Greek fathers into the Latin tongue. Dominic Vallarsi's uncompleted edition of Rufous (vol. i. fol. Verona, 1745) contains the De Benedictionibus, the Apologies, the Expositlo Symboli, the Historia Eremitica and the two original books of the Hist. Eccl. See also Migne, Patrol. (vol. xxi. of the Latin series). For the translations, see the various editions of Origen, Eusebius, etc.
- Mark Vessey, 'Jerome and Rufinus', in Frances Young, Lewis Ayres and Andrew Louth, eds, The Cambridge History of Early Christian Literature, (2010), p324
- Mark Vessey, 'Jerome and Rufinus', in Frances Young, Lewis Ayres and Andrew Louth, eds, The Cambridge History of Early Christian Literature, (2010), p325
- Mark Vessey, 'Jerome and Rufinus', in Frances Young, Lewis Ayres and Andrew Louth, eds, The Cambridge History of Early Christian Literature, (2010), p327
- Transl. by Philip R. Amidon, New-York – Oxford
- William Fremantle in Dictionary of Christian Biography iv. 555-560;
- Friedrich Adolf Ebert, Allg. Gesch. d. Litt. d. Mittelalters im Abendlande, i.321-327 (Leipzig, 1889);
- G. Kruger in Hauck-Herzog's Realencyk. für prot. Theol., where there is a full bibliography.