286 CE - Rome splits into two empires. The Roman Emperor at the time Diocletian, thought that the empire had grown too large and was too big to properly manage. His idea was to split the Empire in half and have two different rulers manage their respective half of the empire. The Western Empire was ruled from Rome, the Eastern Empire was ruled from Constantinople (named after Constantine, today the city is known as Istanbul). The Eastern Empire became known as the Byzantine Empire. Constantinople's location between two seas (The Black Sea and the Mediterranean) protected it from attack and offered the perfect spot to control trade between Europe and Asia. The Eastern half of the empire would become much wealthier than the Western half. Great architectural achievements, like the Hagia Sophia (see photo to the left), and beautiful mosaics (pictures made with pieces of colored stone or glass) were among the many cultural contributions of the Byzantine Empire.