The Western Roman Empire was the western half of the Roman Empire after its administrative division by Diocletian in 285 AD and its final political separation following the death of Theodosius I in 395 AD. While the Eastern Roman Empire (Byzantine Empire) flourished, the West struggled with economic decline, political instability, and relentless invasions by Germanic tribes such as the Visigoths, Vandals, and Franks. The empire's capital was moved from Rome to Mediolanum (Milan) and later to Ravenna in 402 AD, as it was more defensible. The 5th century was marked by the sack of Rome by Alaric I in 410 AD and by the Vandals in 455 AD. The empire effectively ended in 476 AD when Odoacer, a Germanic chieftain, deposed the last emperor, Romulus Augustulus, marking the traditional end of Ancient Rome and the beginning of the Middle Ages in Europe.