Romulus Augustulus
Flavius Romulus Augustus (c. AD 460 – after AD 476; possibly still alive as late as AD 507), known derisively and historiographically as Romulus Augustulus, was the Roman emperor who ruled the Western Roman Empire from 31 October 475 until 4 September 476. He is often described as the "last Western Roman emperor", though some historians consider this to be Julius Nepos. His deposition by Odoacer traditionally marks the end of the Roman Empire in the West, the end of Ancient Rome, and the beginning of the Middle Ages in Western Europe.
East Roman army
In 395, the death of the last sole Roman emperor, Theodosius I (r. 379-95), led to the final split of the empire into two political entities, the West ("Occidentale") and the East ("Orientale"). The system of dual emperors (called "Augusti" after the founder of the empire, Augustus) had been instituted a century earlier by the great reforming emperor Diocletian (r.284-305). But it had never been envisaged as a political separation, purely as an administrative and military convenience. Decrees issued by either emperor were valid in both halves and the successor of each "Augustus" required the recognition of the other. The empire was reunited under one emperor under Constantine I, after 324, under Constantius II, after 353, under Julian, after 361, and Theodosius himself, after 394.