Constantine the Great moved the capital of the Roman Empire to the former Byzantium in Thrace and renamed it Constantinopolis, present day Istanbul, Turkey. Numismatists, for convenience, have arbitrarily categorized coins from Anastasius I and after as Byzantine coins. Numismatists use Anastasius as the beginning of Byzantine because he dramatically reformed the bronze coinage. A significant minority of numismatists pick an earlier time and ruler, often Constantine the Great, as the dividing time between the Roman and Byzantine empires, because most coins were issued from Constantinople, or since it became the seat of government. Although the citizens generally spoke Greek, they considered themselves Roman for the entire Byzantine period, making our division of the empire an entirely modern convention.