Timeline of the Roman Empire
This is a timeline of the history of the Roman Empire and only includes important legal and territorial changes and political events in the Empire from its founding in 27 BC by the Roman Emperor Augustus until the fall in the West in 467 AD and the transition in the East in 610. To read about the background to these events, see History of the Roman Empire.
Gaius Octavian, great-nephew and adoptive son of Julius Caesar, defeated Roman general Mark Antony and Egyptian Queen Cleopatra VII at the Battle of Actium in 31 BC, becoming the sole master of the Roman world. After a series of constitutional settlements between Octavian and the Roman Senate, Octavian was named "Augustus": the first Roman Emperor. The Roman Empire, and the successors of Augustus, would rule the ancient world, stretching across three continents, for almost five centuries.
Julio-Claudian Dynasty (27 BC to 69 AD) 
The Julio-Claudian dynasty was a family of five emperors that governed the Empire during its formative years. All members of the dynasty drew political power from their family ties to Julius Caesar and Augustus. While members often acted in deposit manners, the key principle of the dynasty was upholding the Republic facade of the Empire, known as the Principate, in which the Emperors were not seen as monarchs buts as "first citizen".
30s BC 
- 31 BC - Octavian defeats Marc Antony and the Egyptian Queen Cleopatra VII at the Battle of Actium, becoming the undisputed master of the Roman world
- 30 BC - Octavian is named "Pharaoh", annexes Egypt, and bring the final war of the Roman Republic to a close
20s BC 
- 29 BC -
- 27 BC - Octavian is proclaimed "Augustus" by the Roman Senate and becomes the first Roman Emperor.
- 25 BC -
- Marcus Claudius Marcellus, Augustus' nephew by his sister Octavia Minor, is married to Augustus' only daughter Julia the Elder. Marcellus becomes Augustus' apparent choice as successor.
- Following the death of Amyntas of Galatia, a Roman client king, Augustus annexes his kingdom into the Empire as the province of Galatia.
- 23 BC - Marcellus dies of illness at age 19, leaving Augustus without clear successor.
- 21 BC - Marcus Vipsanius Agrippa, Augustus' close friend and chief military commander, is married to Julia the Elder. Agrippa becomes Augustus' apparent choice as successor.
10s BC 
- 19 BC - The Cantabrian Wars come to an end, completing the Roman conquest of Hispania
- 17 BC - Augustus adopts his grandsons by Agrippa and Julia, Gaius Caesar and Lucius Caesar, as his sons
- 16 BC - Under orders from Augustus, general Tiberius annexes Raetia and Noricum into the Empire
- 12 BC -
- 11 BC - Augustus forces his stepson by Livia, the general Tiberius, to divorce his beloved wife Vipsania Agrippina, a daughter of Agrippa, and to marry his Julia the Elder. Tiberius becomes Augustus' apparent choice as successor.
0s BC 
- 9 BC -
- 6 BC - Augustus grants Tiberius tribunican power and military command over the eastern half of the Empire, guaranteeing his position as Augustus' designated successor. Tiberius, however, retires to the island of Rhodes, leaving Augustus without a clear heir.
- 2 BC - Julia the Elder, Augustus' only daughter and wife of Tiberius, is convicted of adultery and treason. Tiberius divorces her and Augustus exiles her to the island of Pandateria, where she would remain until her death in 14 AD.
0s AD 
- 2 - Lucius Caesar, adoptive son of Augustus and a presumptive heir, dies of illness at age 19. In response, Augustus allows Tiberius to return from retirement as a private citizen.
- 4 - Gaius Caesar, adoptive son of Augustus and a presumptive heir, dies of wounds from military campaign at age 24. With no other possible candidate for succession, Augustus adopts his stepson Tiberius as his son and full heir. Tiberius is made second only to Augustus.
- 6 -
- 9 -
- Under orders from Augustus, the generals Tiberius and Germanicus crush the Great Illyrian Revolt, restoring Roman control to the Balkans. Illyricum is divided into the provinces of Pannonia and Dalmatia
- General Publius Quinctilius Varus is killed at the Battle of Teutoburg Forest, destroying the Roman army presence in Germania
10s AD 
- 10 - General Tiberius assumes command of Roman forces in Germania and begins a two-year counterattack against Germanic tribes
- 13 - Tiberius returns to Rome, where his powers are made equal to those of Augustus, effectively making him "Co-Emperor" in all but title.
- 14 -
- Augustus dies of natural causes at age 75 after a 40 year reign. His step-son and adoptive son Tiberius becomes Emperor.
- Following Augustus' death, soldiers in Germania and Pannonia protested their terms of military service. The new Emperor Tiberius sends Germanicus, the son of Tiberius' brother Nero Claudius Drusus and Tiberius' adoptive son, to Germania and sends his biological son Drusus Julius Caesar to Pannonia to put down the respective revolts.
- 15 - Sejanus becomes Prefect of the Praetorian Guard and a close advisor to Tiberius.
- 16 - General Germanicus defeats Germanic tribes at the Battle of Weser River, reasserting Roman domination in Germania lost after the Battle of Teutoburg Forest
- 17 -
- 18 - Tiberius grants Germanicus, who is immensely popular with the Roman people and Tiberius' heir apparent, military command over the Eastern half of the Empire.
- 19 - Germanicus dies under mysterious circumstances at the age of 33.
20s AD 
- 22 - Drusus Julius Caesar, Tiberius' son, is granted powers second only to Tiberius, becoming his clear successor.
- 23 - Drusus dies under mysterious circumstances at the age of 36. Tiberius is left with no clear successor.
- 26 - Tiberius withdraws to the island of Capri, where he would remain until his death in 37. With Tiberius absent, Sejanus, Prefect of the Praetorian Guard, is left as de facto ruler of Rome.
- 29 - Livia, widow of Augustus and mother to Tiberius, dies of natural causes
30s AD 
- 31 -
- 35 - Tiberius names Caligula and Tiberius Gemellus, Tiberius' biological grandson, as his joint-heirs
- 37 - Tiberius dies of natural causes at age 77 after a 23 year reign. His adoptive grandson and designated heir Caligula becomes Emperor.
- 38 - Caligula orders Tiberius Gemellus executed for treason
40s AD 
- 40 - During a state visit to Rome, Ptolemy of Mauretania, Roman client king of Mauretania, is murdered by Caligula. Maurentania revolts against Roman domination.
- 41 -
- Caligula sends the general Gaius Suetonius Paulinus to suppress the revolt in Mauretania
- Caligula is assassinated by the Praetorian Guard at the age of 28 after a 4 year reign. His uncle Claudius becomes Emperor
- Claudius names Agrippa I as Roman client king of Judea, restoring the province to its status a client kingdom
- 43 -
- 44 - General Gaius Suetonius Paulinus crushes the revolt in Mauretania, annexing the kingdom into the Empire. Claudius divides the territory into the provinces of Mauretania Caesariensis and Mauretania Tingitana
- 46 - Rhoemetalces III, Roman client king of the Odrysian Kingdom, is assassinated in an anti-Roman revolt. Claudius suppresses the revolt and annexes the kingdom into the Empire as the province of Thracia
- 48 - Claudius names Agrippa II as Roman client king of Judea
50s AD 
- 50 - Claudius adopts Nero, the son of his fourth wife Agrippina the Younger
- 53 - Claudius accepts Nero as his heir, to the detriment of Britannicus, his son by his first wife Valeria Messalina
- 54 - Claudius is poisoned by his fourth wife Agrippina the Younger at the age of 63 after a 14 year reign. His step-son and adoptive son Nero becomes Emperor.
60s AD 
- 64 - The Great Fire of Rome takes place.
- 66 - The inhabitants of Judaea revolt against Roman rule, beginning a seven-year war with the Empire. Nero appoints the general Vespasian to suppress the revolt
- 68 - Nero, following a revolt by provincial governors and the Praetorian Guard, commits suicide at the age of 30 after a 14 year reign. A civil war begins to determine his successor.
Flavian Dynasty (69 to 96) 
The Flavian dynasty rose to power during the civil war of 69, known as the Year of the Four Emperors. Although the dynasty proved to be short-lived (with three emperors reigning only 27 years), several significant historic, economic and military events took place during their reign.
- 69 - Following the civil war of 68, general Vespasian emerges victorious and is proclaimed by the Senate as Emperor
- 70 - As part of the Roman response to the Great Jewish Revolt, the general Titus lays siege to Jerusalem, destroying the Great Jewish Temple
- 73 - Lucilius Bassus, military governor of Judea, lays siege to Masada, ending the Great Jewish Revolt
- 77 - Gnaeus Julius Agricola is appointed military governor of Britain, consolidates Roman control over the island, and expands Roman domination into Wales and Scotland
- 79 -
- 81 - Titus dies of fever at the age of 41 after a 2 year reign. His younger brother Domitian becomes Emperor.
- 85 - Gnaeus Julius Agricola, military governor of Britain, returns to Rome after successful campaigns in Britain and its honored by Emperor Domitian.
- 86 - Dacians under King Decebalus cross the Danube river and invade the Roman province of Moesia, beginning a two-year war with the Empire
- 88 - Following a Roman victory against the Dacians at Tapae, the Dacian King Decebalus sues for peace. Domitian grants favorable terms to Decebalus, with Dacia becoming a Roman client kingdom and receives massive annual subsidies
- 89 -
- 96 - Domitian is assassinated by members of his own court at the age of 44 after a 15 year reign. The Senate proclaims the elderly Nerva as Emperor
Nerva–Antonine Dynasty (96 to 192) 
The Nerva–Antonine dynasty were seven Emperors who ruled the Roman Empire from 96 to 192. The dynasty began when the Senate proclaimed Nerva as Emperor following the assassination of Emperor Domitian. The first five of the six successions within this dynasty were notable in that the reigning Emperor adopted the candidate of his choice to be his successor. The Emperor Marcus Aurelius would be the only Emperor of this dynasty to be succeeded by his biological son, the Emperor Commodus. Commodus' assassination would plunge the Empire into a civil war, known as the Year of the Five Emperors.
- Nerva (96-98)
- Trajan (98-117)
- Hadrian (117-138)
- Antoninus Pius (138-161)
- Marcus Aurelius (161-180)
- Lucius Verus (161-169)
- Commodus (180-192)
- 96 - Following the assassination of Domitian, the Senate proclaims the elderly Nerva as Emperor
- 97 - Facing military opposition to his reign, Nerva adopts the popular and successful general Trajan as his son and heir
- 98 - Nerva dies of natural causes at the age of 67 following a 2 year reign. His adoptive son, the general Trajan, becomes Emperor without opposition
- 101 - As part of his conquest of Dacia, Trajan crosses the Danube river and launches an invasion of Dacia, defeating the Dacian King Decebalus at Tapae
- 102 - Trajan approves a peace treaty unfavorable to Decebalus, though Dacia remains a Roman client kingdom
- 105 - Unhappy with his peace treaty with Rome, Dacian King Decebalus crossed the Danube river and raids Roman cities in Moesia. In response, Trajan crosses the Danube river and launches an invasion as part of his conquest of Dacia,
- 106 - Defeating the Dacians at the Battle of Sarmisegetusa, Trajan brings his Dacian wars to an end with the annexation of Dacia into the Empire as a province
- 107 - Rabbel II Soter, Roman client king of Nabataea, dies. Trajan annexes his kingdom into the Empire as the province of Arabia Petraea
- 113 - Trajan begins his invasion of the Parthian Empire
- 114 - Trajan deposes Parthamasiris of Armenia, a Roman client king, and annexes his kingdom into the Empire
- 116 -
- 117 -
- 118 - Hadrian withdraws from the Parthian Empire, returning the recently acquired provinces of Armenia, Mesopotamia, and Assyria to their status prior to Trajan's war
- 119 - Hadrian arrives in Britannia to suppress a revolt
- 122 - Construction of Hadrian's Wall in Britannia begins
- 123 - Hadrian arrives in Mauretania to suppress a revolt
- 124 - Hadrian arrives in Greece to experience Hellenistic culture
- 126 - Hadrian returns to Rome and his ordered reconstruction of the Pantheon begins
- 130 - Hadrian's anti-Jewish policies while in Judea sparks the Bar Kokhba revolt
- 135 - Hadrian defeats the Bar Kokhba revolt, suppressing Jewish political autonomy and religious freedom, renaming "Judea" as "Syria Palaestina"
- 136 - Hadrian names Lucius Aelius Caesar as his adoptive son and heir
- 138 -
- Lucius Aelius Caesar, Hardian's adoptive son and heir, dies of natural causes
- Hadrian names Antoninus Pius as his adoptive son and heir on the condition that he, in turn, adopt Marcus Aurelius and Lucius Verus as his heirs
- Hadrian dies of natural causes at the age of 62 after a 21 year reign. His adoptive son Antoninus Pius becomes Emperor
- 161 - Antonius Pius dies of natural causes at the age of 74 after a 23 year reign. His adoptive sons Marcus Aurelius and Lucius Verus become Co-Emperors
- 169 - Lucius Verus dies of plague, leaving his adoptive brother Marcus Aurelius as sole Emperor
- 177 - Marcus Aurelius names his son Commodus as Co-Emperor
- 180 - Marcus Aurelius dies in Danube War at the age of 58 after a 19 year reign. His son Commodus becomes sole Emperor
- 192 - Commodus is assassinated on December 31 by members of his court at the age of 31 after a 15 year reign.
- 193 - A civil war begins to determine Commodus' successor as Emperor
Severan Dynasty (193 to 235) 
The Severan dynasty ruled the Empire between 193 and 235. The dynasty was founded by the general Septimius Severus, who rose to power as the victor of the civil war of 193, known as the Year of the Five Emperors. Although Severus successfully restored peace following the upheaval of the late 2nd century, the dynasty was disturbed by highly unstable family relationships and constant political turmoil.
- Septimius Severus (193-211)
- Caracalla (198-217)
- Geta (209-211)
- Macrinus (217-218)
- Elagabalus (218-222)
- Alexander Severus (222-235)
- 193 - Following the civil war of 193, general Septimius Severus emerges victorious and becomes Emperor
- 198 - Septimius Severus names his eldest son Caracalla as Co-Emperor
- 209 - Septimius Severus names his youngest son Geta as Co-Emperor with himself and Caracalla
- 211 - Septimius Severus dies of natural causes at the age of 65 after an 18 year reign. His sons Caracalla and Geta rule the Empire jointly as Co-Emperors
- 211 - Geta is assassinated by his brother Caracalla at the age of 22 after an 11 month reign. Caracalla becomes sole Emperor
- 217 - Caracalla is assassinated by members of his bodyguard at the age of 29 after a 19 year reign. His Prefect of the Praetorian Guard, Macrinus, becomes Emperor
- 218 - Following a military revolt, Macrinus is executed at the age of 53 after a 13 month reign. Septimius Severus' great-nephew Elagabalus becomes Emperor
- 222 - Elagabalus is assassinated by the Praetorian Guard at the age of 18 after a 4 year reign. His cousin Alexander Severus, another great-nephew of Septimus Severus, is proclaimed Emperor by the Guard.
- 235 - Following a military revolt, Alexander Severus is assassinated by his own troops at the age of 26 after a 13 year reign. The army proclaims the general Maximinus Thrax as Emperor, beginning a fifty-year political and military crisis.
Crisis of the Third Century (235 to 285) 
The Crisis of the Third Century was a period in which the Roman Empire nearly collapsed under the combined pressures of invasion, civil war, plague, and economic depression. The Crisis began with the assassination of Emperor Alexander Severus at the hands of his own troops, initiating a fifty-year period in which dozens of claimants to the Imperial throne (with dozens more usurpers and pretenders), mostly prominent Roman Army generals, assumed imperial power over all or part of the Empire. In 260, the Empire split into three competing states: the western Gallic Empire, the eastern Palmyrene Empire, and the Roman Empire proper in the center. The Emperor Aurelian reunited the three states into a single Empire by 274. The Crisis ended with the ascension and reforms of Diocletian.
The Crisis resulted in such profound changes in the Empire's institutions, society, economic life and, eventually, religion, that it is increasingly seen by most historians as the transition period between the historical periods of Classical antiquity and late antiquity.
- Maximinus Thrax (235-238)
- Gordian I (238)
- Gordian II (238)
- Pupienus and Balbinus (238)
- Gordian III (238-244)
- Philip the Arab (244-249)
- Decius (249-251)
- Herennius Etruscus (251)
- Trebonianus Gallus (251-253)
- Volusianus (251-253)
- Aemilian (253)
- Valerian (253-260)
- Gallienus (253-268)
- Claudius Gothicus (268-270)
- Quintillus (270)
- Aurelian (270-275)
- Marcus Claudius Tacitus (275-276)
- Florianus (276)
- Probus (276-282)
- Carus (282-284)
- Carinus (282-285)
- 235 - Following the assassination of Severus Alexander during a military revolt, the army proclaims Maximinus Thrax as Emperor
- 238 - Maximinus Thrax is assassinated in a military revolt at the age of 65 after a 3 year reign. His assassination results in a civil war to determine his successor:
- Gordian I and his son Gordian II become Co-Emperors for one month, ending with a military revolt in which Gordian II died in battle and Gordian I committing suicide following the military defeat
- Pupienus and Balbinus become Co-Emperors for three months, ending with their assassination by the Praetorian Guard
- Gordian III, grandson of Gordian I, is proclaimed Emperor by the Praetorian Guard, ending the civil war of 238
- 244 - Gordian III dies from unknown causes after a military defeat at the age of 19 after a 6 year reign. His Prefect of the Praetorian Guard Philip the Arab proclaims himself Emperor.
- 249 - Following a military revolt, Philip the Arab dies at the age of 45 after a 5 year reign. The general Decius is proclaimed Emperor by his troops after defeating Philip the Arab in combat
- 251 - Decius names his son Herennius Etruscus as Co-Emperor.
- 251 - Decius and Herennius Etruscus are killed in battle by the Goths. Trebonianus Gallus and his son Volusianus are proclaimed Emperor by the army
- 253 - In a military revolt, Trebonianus Gallus and son Volusianus are murdered by their own troops. The army proclaims Aemilian Emperor
- 253 - In a military revolt, Valerian is proclaimed Emperor by the army. He names his son Gallienus Co-Emperor
- 260 - Valerian is captured by the Sassanid Empire after a military defeat, becoming a Persian prisoner of war, ending his 7 year reign. His son Gallienus becomes sole Emperor
- 260 - The Gallic Empire (the provinces of Britainnia, Hispannia, and Gaul) and the Palmyrene Empire (the provinces of Syria, Egypt, and Asia) secede from the Empire, becoming separated from Imperial control
- 268 - In a military revolt, Gallienus is killed at the age of 50 after a 15 year reign. His general Claudius Gothicus is proclaimed Emperor by the army
- 270 - Claudius Gothicus dies of illness at the age of 56 after a 2 year reign. His brother Quintillus proclaims himself Emperor with the support of the Senate while Claudis' general Aurelian is proclaimed Emperor by the army. Aurelian defeats Quintillus in battle and is recognized as Emperor by the Senate
- 273 - Aurelian defeats Queen Zenobia, ruler of the Palmyrene Empire, and reunites the eastern provinces into the Empire
- 274 - Aurelian defeats Emperor Tetricus I, ruler of the Gallic Empire, and reunites the western provinces into the Empire
- 275 - Aurelian is assassinated by the Praetorian Guard at the age of 60 after a 5 year reign. The Senate elects, with ratification by the army, Marcus Claudius Tacitus as Emperor
- 276 - Marcus Claudius Tacitus dies of fever at the age of 76 after a 9 month reign. His Prefect of the Praetorian Guard, Florianus, is proclaimed Emperor by the army
- 276 - In a military revolt, Florianus is assassinated by his own troops after a 3 month reign. Marcus Aurelius Probus, former Emperor Tacitus' half-brother, is proclaimed Emperor by the army
- 282 - In a military revolt, Probus is assassinated by his own troops at the age of 50 after a 6 year reign. His Prefect of the Praetorian Guard, Carus, is proclaimed Emperor by the army. Carus names his sons Carinus and Numerian as junior Emperors, with Carinus in the West and Numerian in the East.
- 283 - Carus dies of natural causes at the age of 59 after a 1 year reign. His son Carinus and Numerian become Co-Emperors
- 284 - Numerian dies of disease while on military campaign, allowing his older brother Carinus to become sole Emperor
- 284 - Diocletian begins a revolt against Carinus, proclaiming himself Emperor with the support of the Eastern army.
- 285 - Diocletian defeats Carinus in battle, with Carinus killed by his own troops. Diocletian is proclaimed Emperor by both the western and the eastern armies. The fifty-year military and political crisis comes to an end.
Diocletian and the Tetrarchy (285 to 313) 
When Diocletian was proclaimed Emperor, he ruled the entire Empire as sole Emperor. Diocletian named Maximian as his Co-Emperor in 286, through Diocletian remained the senior partner. He then established a system for governing the Empire by four rulers known as the Tetrachy: two Senior Emperors (Augustii) and two Junior Emperors (Caesars'), with one Senior and Junior Emperor (the designated heir) in the West and East respectively. Diocletian, and his successors, become Senior Emperor of the East and Maximian, and his successors, Senior Emperor in the West. The Tetrachy was relatively stable until the death Constantius Chlorus in 306, which started a civil war to determine the true successor to the Western throne. The Tetrarchy system ended in 313 with the death of Eastern Emperor Maximinus II, when internecine conflict eliminated most of the claimants to power, leaving Constantinus' son Constantine I as Western Emperor and Licinius as Eastern Emperor.
- Diocletian (285-305)
- Maximian (286-305)
- Galerius (305-311)
- Constantius Chlorus (305-306)
- Flavius Valerius Severus (306-307)
- Constantine the Great (307-337)
- Maxentius (307-312)
- Maximinus II (310-313)
- Licinius (313-324)
- 285 - Diocletian defeats Carinus in military combat, ending a fifty-year military and political crisis and becomes sole Emperor
- 285 - Diocletian appoints Maximian as "Caesar" and Junior Emperor
- 286 - Diocletian elevates Maximian to "Augustus" and Co-Emperor, with Diocletian as Eastern Emperor and Senior Emperor and Maximian as Western Emperor
- 293 - With Diocletian's blessing, Constantius Chlorus is appointed by Maximian as "Caesar" and Junior Emperor in the West.
- 293 - Diocletian appoints Galerius as "Caesar" and Junior Emperor in the East.
- 304 - Galerius convinces Diocletian to designte Galerius’s nominees Flavius Valerius Severus and Maximinus II as "Caesars" upon Constantius Chlorus and Galerius elevation to "Augustii".
- 305 - Diocletian and Maximian retire simultaneously from their Imperial thrones. Constantius Chlorus becomes "Augustus" and Senior Emperor in the West and Galerius becomes "Augustus" and Senior Emperor in the East. Severus becomes "Caesar" and Junior Emperor in the West and Maximinus II becomes "Caesar" and Junior Emperor in the East.
- 306 - Constantius Chlorus dies of natural causes at the age of 56 while on military campaign in Britannia. He convinces his army to proclaim his son Constantine his successor as "Augustus" of the West instead of the "Caesar" Severus.
- 306 - Eastern "Augustus" Galerius recognizes Constantine as "Caesar" in the West and elevates Severus to "Augustus" of the West
- 306 - Maxentius, son of the former Western "Augustus" Maximian, rebels against the legitimate Western "Augustus" Severus
- 307 - Severus is defeated and killed by the usurper Maxentius, who assumes the title "Augustus" of the West
- 308 - Eastern "Augustus" Galerius reaffirms Constantine as Western "Caesar" and appoints Licinius as Western "Augustus" with instructions to defeat the usurper Maxentius
- 309 - The former Western "Augustus" Maximian and his son the usurper Maxentius have a falling out, with Maximian fleeing to the protection of Constantine
- 310 - Following a failed revolt against Constantine, the former Western "Augustus" Maximian commits suicide
- 311 - Eastern "Augustus" Galerius dies of natural causes at the age of 51. His nephew and the Eastern "Caesar" Maximinus II succeeds him as Eastern "Augustus"
- 311 - Maximinus II, the Eastern "Augustus", and Licinius, the Western "Augustus", enter a power-sharing agreement, both becoming Co-Emperors of the East
- 311 - Constantine and Licinius declare an alliance through the marriage of Licinius to Constantine's half-sister Flavia Julia Constantia
- 311 - Following the alliance of Constantine and Licinius, Maximinus II enters a secret alliance with the usurper Maxentius
- 312 - Constantine defeats and kills the usurper Maxentius, becoming undisputed Western Emperor. Following his victory, Constantine converts to Christianity
- 313 - Licinius defeats his Co-Eastern Emperor Maximinus II, becoming undisputed Eastern Emperor
Constantinian Dynasty (313 to 363) 
- Constantine the Great (313-337)
- Licinius (313-324)
- Constantine II (337-340)
- Constantius II (337-361)
- Constans (337-350)
- Julian the Apostate (360-363)
- Jovian (363-364)
- 313 - With the defeat of Maximinus II, the Tetrarchy ends. Constantine I rules as Emperor in the West while Licinius rules as Emperor in the East
- 324 - Constantine I defeats Licinius in battle and becomes sole Emperor
- 337 - Constantine I dies of natural causes at the age of 65 after a 31 year reign. His sons Constantine II, Constantius II, and Constans become Co-Emperors and divide the Empire among themselves:
- Constantine II rules the provinces of Britannia, Hispannia, Gaul, and Illyria
- Constantius II rules the provinces of Asia, Syria, and Egypt
- Constans rules the provinces of Italy and Africa, with Constans placed under the guardianship of Constantine II
- 338 - Constans, unhappy with the division of power, petitions his brothers to redivide the Empire, with Constans receiving Illyria from Constantine II
- 340 - Despite Constans reaching adulthood, Constantine II refuses to relinquish guardianship over his younger brother. Constantine II marches to Italy to enforce his authority, where he is defeated in battle by Constans, who assumes control over his deceased brother's territory.
- 350 - In a military revolt led by the usurper Magnentius, Constans is murdered by his own troops at the age of 27 after a 14 year reign.
- 353 - Constantius II defeats the usurper Magnentius in battle and becomes sole Emperor
- 360 - Julian the Apostate is proclaimed Emperor by the western army
- 361 - Constantius II dies of natural causes at the age of 44 after a 24 year reign, averting a civil war with Julian. Constantius' will names Julian as his lawful successor, making Julian sole Emperor
- 363 - While campaigning against the Sassanid Persians, Julian as mortally wounded in battle and dies at the age of 31. The commander of his Imperial Guard, Jovian is proclaimed Emperor by the army
- 364 - Following the signing of a peace treaty with the Persians on humiliating terms, Jovian dies under mysterious circumstances. The army proclaims the general Valentinian I as Emperor
Valentinian Dynasty (364 to 395) 
- Valentinian I (364-375)
- Valens (364-378)
- Gratian (375-383)
- Valentinian II (375-392)
- Theodosius I (378-395)
- 364 - Following the mysterious death of Jovian, the army proclaims Valentinian I as Emperor. To prevent a succession crisis, Valentinian I appoints his younger brother Co-Emperor, with Valentinian I as Western Emperor and Valens as Eastern Emperor
- 375 - Valentinian I dies of a stroke at the age of 54 following a 12 year reign. His sons Gratian and Valentinian II succeed him as Co-Emperors of the West
- 376 - Fleeing Hunnic aggression, the Goths under the leadership of Fritigern cross the Danube River and enter the Eastern Empire as political refugees
- 377 - Following harsh treatment by the Romans, the Goths revolt and begin the Gothic War
- 378 -
- 382 - Following a joint east-west military campaign, the Goths and the Empire conclude a peace treaty in which the Goths are allowed to settle along the southern Danube frontier in the province of Thrace and are granted significant self-governance
- 383 - In a military revolt, Gratian is murdered by his own troops at the age of 24 after an 8 year reign. His half brother Valentinian II becomes sole Western Emperor
- 392 - Valentinian II dies under mysterious circumstances (either suicide or murder) at the age of 21 after a 17 year reign. Eastern Emperor Theodosius becomes sole Emperor
- 395 - Theodosius dies of illness at the age of 48 following a 16 year reign. Theodosius' death permanently divides the Empire into Western and Eastern halves, with his oldest son Arcadius as Eastern Empire and youngest son Honorius as Western Emperor.
Western Empire (395 to 476) 
The Western Roman Empire existed intermittently in several periods between the 3rd and 5th centuries, after Emperor Diocletian's Tetrarchy and then after the reunifications associated with Emperors Constantine the Great and Julian the Apostate. Emperor Theodosius I was the last Emperor to rule over an unified Empire. After his death in 395, the Empire was permanently divided into Eastern and Western halves. Following the final division, the Western Empire would survive for eight decades under increased barbarian invasions, eventually falling under the pressure of internal revolt and foreign invasion in the mid-5th century.
Theodosian Dynasty (395 to 455) 
The Theodosian dynasty ruled the Western Empire for fifty years. Following the death of Emperor Theodosius I in 395 and the permanent division of the Empire, Theodosius' eleven-year old son Honorius became Western Emperor. The Emperor Honorius named Constantius III the Supreme Commander of the Western Army and husband of the Emperor's sister Galla Placidia, as Co-Emperor in 421. He reigned alongside Honorius briefly until he died suddenly after only seven months as Emperor. Following Honorius' death in the first quarter of the 5th century, a brief interim existed during which the Western throne remained legally vacant, though usurpers attempted to claim the throne. Supported by the Eastern court, six-year old Valentinian III, the son of Constantius and Placidia, became Emperor. Both members of the Theodosian dynasty were mostly ceremonial figureheads as both Emperors were dominated by powerful military commanders, who were the power behind the throne in the West.
- 395 -
- Following the death of Emperor Theodosius I, the Western and Eastern halves of the Empire are divided with Theodosius' ten year-old son Honorius becoming Emperor in the West
- Given Honorius' young age (11 at the time), the Supreme Commander of the Western Army, the half-Vandal Stilicho, becomes the Emperor's regent and power behind the throne
- 398 - Supeme Commander Stilicho puts down the Gildonic revolt led by Count of Africa Gildo to defect to the Eastern Empire.
- 402 - The capital of the Western Empire moves from Milan to Ravenna
- 406 - On New Year's Eve, the Vandals, Alans, and Suebi cross the frozen Rhine River and invade the Empire through Gaul
- 410 -
- 421 -
- Honorius names the Supreme Commander of the Western Army Constantius III as his Co-Emperor
- After only seven months as Co-Emperor, Constantius III dies suddenly
- 423 - Honorius dies of edema at the age of 39 after a 28-year reign. With no heir to the Western throne, the West experiences an interregnum in which the usurper Joannes takes power in Rome
- 424 - Eastern Emperor Theodosius II names his cousin Valentinian III, son of Galla Placidia and Constantius III, as Western Emperor
- 425 - The usurper Joannes is defeated by Eastern General Aspar, who installs the six year-old Valentinian III as Western Emperor. Due to his minority status, the Emperor's mother Placidia becomes his de facto regent as the true power behind the throne.
- 455 - Upon the orders of Senator Petronius Maximus, Valentinian III is assassinated in Rome at the age of 35 after a 29 year reign.
Non-dynastic (455 to 476) 
Following the assassination of the Valentinian III, the western branch of the Theodosian dynasty ended. The final 21 years of the Western Empire would witness the imperial throne change hands nine times with a two-year interregnum, with each Emperor ruling on average a little over two years each. The central figure during the final two decades of the West was the Supreme Commander of the Western Army Ricimer who, despite being unqualified to hold the tile "Emperor" himself due to his barbarian heritage, effectively ruled the Western Empire for sixteen years as the power behind the throne. He routinely elevates and deposed a series of puppet Emperors. The Eastern Empire attempted to restore stability to the West, twice sending an Eastern-backed Emperor to claim the Western throne. The last legitimate Western Emperor was Julius Nepos, who was sent by Eastern Emperor Zeno. Despite initial success, Julius Nepos was deposed by his own general, who in turn appointed his son, the child Romulus Augustulus, as Western Emperor. Romulus Augustus, who was never recognized as Emperor by the East, was forced to abdicate following a barbarian revolt on September 4, 476. The Senate then sent Eastern Emperor Zeno the Western regalia, legally ending the separate Western Empire.
- Petronius Maximus (455)
- Avitus (455-456)
- Majorian (457-461)
- Libius Severus (461-465)
- Anthemius (467-472)
- Olybrius (472)
- Glycerius (473-474)
- Julius Nepos (474-475)
- Romulus Augustus (475-476)
- 455 - Following his assassination of Valentinian III, Senator Petronius Maximus is declared Emperor by the Senate, through the Eastern Emperor refuses to recognize his positions and considers him a usurper
- 455 - After a two-month reign, Maximus Petronius is deposed by an angry mob who stoned him to death as he attempted to flee Rome as the Vandal's advanced on the City
- 455 - The Vandals under King Geiseric sack the City of Rome
- 455 - Upon hearing of the deposition of Petronius, Visigothic King Theodoric II proclaims General Avitus as Western Emperor.
- 456 - In a military rebellion led by Count of the Imperial Guard Majorian and Supreme Commander of the Western Army Ricimer, Avitus is deposed and forced into exile after a fifteen-month reign
- 457 - Following his appointment as General of the Western Army by the Eastern Emperor Leo I, Majorian is proclaimed Western Emperor by the Western Army and is begrudgingly recognized as such by the Eastern Emperor
- 461 - Majorian is deposed and murdered by Ricimer at the age of 40 following a four-year reign. Ricimer waited three months before installing the weak Senator Libius Severus as his puppet Western Emperor. The new emperor was not recognized by the Eastern Emperor Leo I, nor by any of the generals who had served under Majorian.
- 465 - Libius Severus dies of natural causes at the age of 45 following a four-year reign. Ricimer proceeds to rule the Western Empire without an Emperor.
- 467 - Under increased assault from the Vandals, Eastern Emperor Leo, with the consent of Ricimer, names the Eastern General Anthemius as Western Emperor. Anthemius leads an Eastern Army to Italy with orders to recapture North Africa from the Vandals.
- 472 -
- In a military revolt lead by Ricimer, Anthemius is killed at the age of 52 following a five-year reign. Ricimer names Olybrius as puppet Western Emperor
- Ricimer dies of plague at the age of 67 after effectively ruling the Western Empire for sixteen years. His nephew Gundobad becomes Supreme Commander of the Western Army and the power behind the Western throne
- After only a seven-month reign, Olybrius dies of dropsy at the age of 41. Despite the objections of the Eastern Emperor Leo I, Gundobad installs Count of the Imperial Guard Glycerius as puppet Western Emperor
- 473 - Following the death of his father Gondioc (King of the Burgundians), Gundobad abandons his positions as Supreme Commander of the Western Army to claim his father's vacant throne
- 474 -
- Eastern Emperor Leo I names the Governor of Dalamtia Julius Nepos as Western Emperor and orders him to depose the usurper Glycerius
- Without the support of Gundobad to protect him, Julius Nepos defeats Glycerius and forces his abdication and, though unpopular with the Senate due to his family ties to the Eastern Empire, becomes undisputed Western Emperor
- 475 -
- Julius Nepos appoints Orestes as Supreme Commander of the Western Army
- Orestes, at the head of foederati units, marches on the capital of Ravenna and forces Julius Nepos to flee Italy for Dalamtia. Though he continued to be recognized as the legitimate Western Emperor by the Eastern Empire, Juliius Nepos never returned to Italy nor exercised any authority outside of Dalamtia.
- Over the objections of the Eastern Emperor Leo I, Orestes names his 12 year-old son Romulus Augustulus as Western Emperor
- 476 -
- After refusing to grant land to his foederati units, the foederati units under Odoacer rebell and kill Orestes.
- Odoacer advanced to Ravenna, capturing the city and forces Romulus Augustus to abdicate the throne on September 4, de facto ending the Western Empire
- The Senate, at Odoacer's request, sends the Western regalia to the Eastern Emperor Zeno, making Zeno the de jure Emperor of a reunited Empire. Odoacer de jure rules Italy as Zeno's representative but de facto exercises independent authority.
Eastern Empire (395 to 610) 
The Eastern Roman Empire was permanently established following the death of Emperor Theodosius I in 395, in which the united Empire was permanently divided into Eastern and Western halves. The Eastern Empire existed as a counterpart to the Western Empire until the West's fall in 476. Following the West's fall, the East and West were de jure reunited as a single Empire. Following the fall of the West, the Eastern Empire would survive for another thousand years. During most of its existence, the East remained one of the most powerful economic, cultural, and military force in Europe, despite setbacks and territorial losses, especially during the Roman-Persian and Roman-Arab Wars. The transition from the Eastern Empire into the Byzantine Empire begins during the reign of Emperor Heraclius as Heraclius effectively established a new state after reforming the army and administration by introducing themes and by changing the official language of the Empire from Latin to Greek.
Theodosian Dynasty (395 to 457) 
Leonid Dynasty (457 to 518) 
Justinian Dynasty (518 to 602) 
Non-dynastic (602 to 610) 
See also 
- History of Rome
- History of the Roman Kingdom
- History of the Roman Republic
- History of the Roman Empire
- History of the Byzantine Empire