History of the Roman Empire
Theodosius was the last Emperor who ruled over the whole Empire. After his death in 395, he gave the two halves of the Empire to his two sons Arcadius and Honorius; Arcadius became ruler in the East, with his capital in Constantinople, and Honorius became ruler in the West, with his capital in Milan and later Ravenna. The Roman state would continue to have two different emperors with different seats of power throughout the 5th century, though the Eastern Romans considered themselves to be the only ones who were fully Roman. Latin was used in official writings as much as, if not more than, Greek and the two halves were nominally, culturally and historically, if not politically, the same state.
Christianity in late antiquity
Christianity in late antiquity traces Christianity during the Christian Roman Empire – the period from the rise of Christianity under Emperor Constantine (c. 313), until the fall of the Western Roman Empire (c. 476). The end-date of this period varies because the transition to the sub-Roman period occurred gradually and at different times in different areas. One may generally date late ancient Christianity as lasting to the late 6th century and the re-conquests under Justinian (reigned 527-565) of the Byzantine Empire, though a more traditional end-date is 476, the year in which Odoacer deposed Romulus Augustus, traditionally considered the last western emperor.