The Byzantine Empire was the eastern half of the Roman Empire that continued after the western half crumbled in the 5th century CE. Emperor Constantine moved the capital to Constantinople to respond to threats from Germanic tribes in the west and the Sasanid Empire in Persia. Under Justinian in the 6th century, General Belisarius recovered territory including North Africa, Italy, and parts of Spain. The Byzantine Empire had an extremely centralized government, a complex bureaucracy, used Greek instead of Latin, and influenced neighboring Slavic peoples through political, commercial, and cultural relations.