, Valentinian II's general-in-chief, murdered him in May 392, and replaced him with a puppet Emperor, Eugenius, a former rhetorician. Eugenius was overthrown two years later by Theodosius I, Valentinian II's brother-in-law.
Much as the Valentinian dynasty was loosely connected to the Constantinian dynasty by marriage, the Theodosian dynasty was loosely connected to the Valentinian; the first Theodosian Emperor, Theodosius I was son-in-law of Valentinian I. Although he was a Hispano-Roman of military background, like Valentinian, he was no "Barracks Emperor"; he was lawfully and voluntarily elevated to the purple in the East by the reigning Emperor Gratian, his half-brother-in-law, on January 19, 379. He abolished paganism entirely and made Christianity the official religion of the Empire in 391, overthrew Arbogast and his puppet Emperor, Eugenius, in the West in 394, and was the last Emperor to rule both East and West.
Theodosius I, 379-5
Final division of the Roman Empire in "East" and "West"
After Theodosius's death in 395, the Empire was permanently divided into East and West by his 17-year-old and 10-year-old sons, Arcadius and Honorius, respectively.
Emperors in the East
Arcadius, 395-408
Theodosius II, 408-50
Marcian, 450-7 — Marcian is the first Emperor to be honored as a saint ; his feast day is Feb. 17.
Emperors in the West
By the time the Visigoths under their king Alaric entered Italy and sacked Rome in 410 - the first time a foreign army had set foot in Rome since 390 BC, some 800 years earlier - Rome had ceased to be capital of the Empire either in East or West ; indeed, by that point in history, the Bishop of Rome was one of the few senior Ecclesiastical or Imperial officials in the Roman Empire to actually reside in Rome.
Honorius, 395-423
*Constantius III, 421
Valentinian III, 425-55
Dynastic Relationships
Theodosius I married twice; first to Aelia Flaccilla, who bore him two sons, and second to Galla, who bore him a daughter. Arcadius's wife Aelia Eudoxia bore him a daughter and a son, who became Emperor at age seven. After Theodosius II's death, his sister Pulcheria married Marcian, a Thracian soldier of common stock. Constantius III married Arcadius's and Honorius's sister Galla Placidia, and she bore him a son, Valentinian III. Valentinian III's wife Licinia Eudoxia bore him a daughter, Placidia, who married Olybrius.
After the Theodosian Dynasty
In the West
The wealthy senator Petronius Maximus, who succeeded Valentinian III, had attempted to secure his position by marrying Valentinian's widow, Licinia Eudoxia. The final collapse of the Empire in the West was marked by increasingly ineffectual puppet Emperors dominated by their Germanic masters of the soldiers. The most pointed example of this is the Suebian general Ricimer, who became a "Shadow Emperor" by deposing Avitus, installing and subsequently deposing Majorian, installing Libius Severus, ruling the Empire himself during an eighteen-month interregnum, deposing and killing Anthemius, and installing Olybrius. His position as "Shadow Emperor" was in turn held by his nephew Gundobad and Orestes; Odoacer simply overthrew Orestes's puppet Emperor, Romulus Augustus, in 476 and ruled Italy as nominal subordinate of the Emperor-in-exile, Julius Nepos, who continued to reign in Dalmatia until 480.
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 "Augustulus", 475–476
Petronius Maximus was killed trying to flee Rome - presently under imminent threat of attack by Geiseric's Vandals - eleven weeks after donning the purple; Rome was plundered but spared a full-fledged sacking due in large part to the intervention of the Bishop of Rome, Pope Leo I, who had previously averted an attack on Rome by Attila the Hun in 452. Petronius Maximus was succeeded by his master of the soldiers, Avitus, who was acclaimed at Tolosa with the backing of the Visigothic king, Theodoric II. Avitus was in turn overthrown by his own master of the soldiers, Ricimer, who was responsible for both the installation and removal of Majorian and of Libius Severus, the removal of Anthemius, and the installation of Olybrius - husband of Valentinian III's daughter Placidia, and loosely a member of the Theodosian dynasty. Both Ricimer and Olybrius died in 472, and were replaced by the Burgundian prince Gundobad and his puppet Emperor Glycerius, a former court functionary. Glycerius was deposed by Julius Nepos, the candidate of the Eastern Emperor, who was in turn driven into exile in Dalmatia in 475 by his master of the soldiers, Orestes, who installed his own son Romulus "Augustulus". Orestes was killed and Romulus deposed by Odoacer in 476, and Julius Nepos continued to reign as Emperor-in-exile until his death in 480.
The East: Leonine Dynasty
The Leonine dynasty was almost totally a marital one, conspicuous for its rather disorderly succession of Emperors. The first Leonine Emperor, the Dacian army officer Leo I, came to power through the machinations of the late Marcian's Alan master of the soldiers, Aspar, who as a result of his barbarian birth and religious heterodoxy was unable to don the purple for himself. The Leonine Emperors also mark the second time a female dynast directly influenced the Imperial succession by marriage: Zeno's widow Ariadne hand-picked Anastasius I to succeed her late husband and married him. Zeno was ruling in Constantinople during the "fall of Rome" in 476, and both Odoacer and his over-thrower Theodoric of the Ostrogoths officially ruled Italy as Zeno's viceroys; this suzerainty was purely theoretical, however, and Imperial control of Italy was not actually reasserted until the conquests of Justinian I's strategosBelisarius in the 530s.
Leonine Emperors
Leo I, 457–474
Leo II, 474
*Zeno, 474
Zeno, 474–491
*Basiliscus, 474–475
Anastasius I, 491–518
Dynastic Relationships
Leo I wife Verina bore him at least two daughters, one of whom married the son of Anthemius, whom Leo I installed as Emperor in the West in 467, and the other of whom was Ariadne, who married the Isaurian leader Tarasikodissa; Tarasikodissa was appointed master of the soldiers and adopted the name Zeno. Ariadne and Zeno had a son, Leo II, who succeeded his grandfather as Emperor in 474 ; Leo II's death left his father sole Emperor in the East, producing the altogether curious spectacle of a grandson succeeding his grandfather without his father's predecease, and then in turn being succeeded by his own father. Zeno was temporarily displaced in Constantinople by Verina's brother Basiliscus, but regained his position as emperor a year later. On his death, Ariadne married the court functionary Anastasius I, and thereby elevated him to Emperor by virtue of marrying the Empress.