Julius Nepos in the context of "Leonid dynasty"

In modern scholarship, the "late" period of the Roman army begins with the accession of the Emperor Diocletian in AD 284, and ends in 480 with the death of Julius Nepos, being roughly coterminous with the Dominate. During the period 395–476, the army of the Roman Empire's western half progressively disintegrated, while its counterpart in the East, known as the East Roman army (or the early Byzantine army) remained largely intact in size and structure until the reign of Justinian I (r. AD 527–565).

The Imperial Roman army of the Principate (30 BC – 284 AD) underwent a significant transformation as a result of the chaotic 3rd century. Unlike the army of the Principate, the army of the 4th century was heavily dependent on conscription and its soldiers were paid much less than in the 2nd century. Barbarians from outside the empire probably supplied a much larger proportion of the late army's recruits than in the army of the 1st and 2nd centuries, but there is little evidence that this adversely affected the army's combat performance.

Odoacer's deposition of Romulus Augustus, occurring in 476 AD, was a coup that marked the end of the reign of the last Western Roman Emperor approved by the Western Roman Senate and the creation of the Kingdom of Italy through Odoacer's decision to adopt the title of Dux/Rex Italiae(Duke/King of Italy), although Julius Nepos exercised control over Dalmatia until 480.

Glycerius (died after 474) was Roman emperor of the West from 473 to 474. He served as comes domesticorum (commander of the palace guard) during the reign of Olybrius (r. 472), until Olybrius died in November 472. After a four-month interregnum, Glycerius was proclaimed as emperor in March 473 by Gundobad, the magister militum (master of soldiers) and power behind the throne. Very few of the events of his reign are known other than that an attempted invasion of Italy by the Visigoths was repelled by local commanders, diverting them to Gaul. Glycerius also prevented an invasion by the Ostrogoths through diplomacy, including a gift of 2,000 solidi.

Glycerius was not recognized by the Eastern Roman emperor Leo I (r. 457–474), who instead nominated Julius Nepos (r. 474–475/480) as Western Emperor and sent him with an army to invade the Western Empire. Glycerius was without allies because Gundobad had abandoned him, and therefore was forced to abdicate on 24 June 474, and was succeeded by Nepos. He was appointed Bishop of Salona, which position he held until his death. He died, possibly in 480, and a nearly contemporaneous source blames him for the assassination of Nepos, but the records for this event are muddled.

Salona (Ancient Greek: Σάλωνα, Latin: Salo) was an ancient city and the capital of the Roman province of Dalmatia and near to Split, in Croatia. It was one of the largest cities of the late Roman empire with 60,000 inhabitants. It was the last residence of the final western Roman Emperor Julius Nepos and acted as the de facto capital of the Western Roman Empire during the years 476-480.

Salona was founded in the 3rd century BC and was mostly destroyed in the invasions of the Avars and Slavs in the seventh century AD.

The Battle of Ravenna, capital of the Western Roman Empire, between the Heruli under their King Odoacer and the remnants of the Western Roman army in Roman Italy occurred in early September 476, and represented a culminating event in the ongoing fall of the Western Roman Empire. The Western Roman Empire had been in relative decline since the beginning of the barbarian invasions and Rome, the symbolical heart and largest city of the Western Empire, was sacked in 410 by the Visigoths and in 455 by the Vandals. By 476 the Roman emperor was little more than a puppet, having very little de facto control of any territory outside of Italy. The last Roman emperor, Romulus Augustulus, was not recognized as a legitimate ruler outside of Italy; the Eastern Roman Empire recognized Julius Nepos as the true Western Roman Emperor.

Herulians were foederati of the Western Roman Empire; they were mercenary troops of the Roman army of Italy. They envied the fortune of their brethren in Gaul, Spain, and Africa, whose victorious arms had acquired an independent and perpetual inheritance; and they insisted that a third part of the lands of Italy should be immediately divided among them. Orestes, the father of emperor Romulus Augustus, rejected their demand – causing their revolt. From all the camps and garrisons of Italy the confederates flocked to the standard of Odoacer, their leader; Orestes later retreated to Pavia. Pavia was subsequently pillaged and Orestes was executed.