Life

Nepotianus married the sister of Marcellinus

Marcellinus (magister militum)

Marcellinus was a Roman general and patrician who ruled over the region of Dalmatia in the Western Roman Empire and held sway with the army there from 454 until his death.-Origins:...

, the semi-independent ruler of Dalmatia; the couple had a son, Julius Nepos

Julius Nepos

Julius Nepos was Western Roman Emperor de facto from 474 to 475 and de jure until 480. Some historians consider him to be the last Western Roman Emperor, while others consider the western line to have ended with Romulus Augustulus in 476...

, last Western Roman Emperor.

In 458 he was comes et magister utriusque militiae and together with Aegidius

Aegidius

Aegidius was a Gallo-Roman warlord of northern Gaul. He had been promoted as magister militum in Gaul under Aëtius around 450. An ardent supporter of Majorian, Aegidius rebelled when Ricimer deposed Majorian, engaging in several campaigns against the Visigoths and creating a Roman rump state that...

, he commanded the army

Late Roman army

The Late Roman army is the term used to denote the military forces of the Roman Empire from the accession of Emperor Diocletian in 284 until the Empire's definitive division into Eastern and Western halves in 395. A few decades afterwards, the Western army disintegrated as the Western empire...

 of the Western Emperor, Majorian

Majorian

Majorian , was the Western Roman Emperor from 457 to 461.A prominent general of the Late Roman army, Majorian deposed Emperor Avitus in 457 and succeeded him. Majorian was one of the last emperors to make a concerted effort to restore the Western Roman Empire...

. That same year Majorian started a military campaign to re-conquer Gaul; the army, reinforced by some barbarian mercenaries, dislodged the Visigoths of Theodoric II

Theodoric II

Theodoric II was King of Visigoths from 453 to 466.Theoderic II, son of Theodoric I, obtained the throne by killing his elder brother Thorismund...

 from Arelate and obliged them to return to their condition of foederati

Foederati

Foederatus is a Latin term whose definition and usage drifted in the time between the early Roman Republic and the end of the Western Roman Empire...

. With the help of his new foederati, Majorian entered in the Rhone Valley, conquering its populations "some by arms and some by diplomacy". He defeated the Burgundians

Burgundians

The Burgundians were an East Germanic tribe which may have emigrated from mainland Scandinavia to the island of Bornholm, whose old form in Old Norse still was Burgundarholmr , and from there to mainland Europe...

 and besieged and conquered the city of Lugdunum

Lugdunum

Colonia Copia Claudia Augusta Lugdunum was an important Roman city in Gaul. The city was founded in 43 BC by Lucius Munatius Plancus. It served as the capital of the Roman province Gallia Lugdunensis. To 300 years after its foundation Lugdunum was the most important city to the west part of Roman...

: the rebel city was heavily fined, while the Bagaudae

Bagaudae

In the time of the later Roman Empire bagaudae were groups of peasant insurgents who emerged during the "Crisis of the Third Century", and persisted particularly in the less-Romanised areas of Gallia and Hispania, where they were "exposed to the depredations of the late Roman state, and the great...

 were forced to join the Empire.

In 459, some envoys of Nepotianus and of the gothic comes Sunieric

Sunieric

Sunieric was a Visigoth general, who collaborated with the Roman army in the re-conquest of Spain on behalf of Emperor Majorian.- Life :...

 arrived in Gallaecia

Gallaecia

Gallaecia or Callaecia, also known as Hispania Gallaecia, was the name of a Roman province and an early Mediaeval kingdom that comprised a territory in the north-west of Hispania...

 to announce the victory of Majorian and the threaty between the Romans and the Visigoths.

In May 460, Nepotianus and Sunieric led some troops in a joint attack with Theodoric to the Suebi

Suebi

The Suebi or Suevi were a group of Germanic peoples who were first mentioned by Julius Caesar in connection with Ariovistus' campaign, c...

: Nepotianus moved to Gallaecia and attacked the Suebic army, defeating it near Lucus Augusti

Lugo

Lugo is a city in northwestern Spain, in the autonomous community of Galicia. It is the capital of the province of Lugo. The municipality had a population of 97,635 in 2010, which makes is the fourth most populated city in Galicia.-Population:...

.

At the beginning of the 460s, Nepotianus was deposed by order of Theodoric II, maybe because he opposed the powerful magister militum Ricimer

Ricimer

Flavius Ricimer was a Germanic general who achieved effective control of the remaining parts of the Western Roman Empire, during the middle of the 5th century...

, and was substituted by Arborius. He died in 465.