As the Western Roman Empire declined during the 5th century, the richer Eastern Roman Empire would be relieved of much destruction, and in the mid 6th century the Eastern Roman Empire (known also as the Byzantine Empire) under the emperor Justinian I reconquered Italy and parts of Illyria from the Ostrogoths, North Africa from the Vandals, and southern Hispania from the Visigoths. The reconquest of southern Hispania was somewhat ephemeral, but North Africa served the Byzantines for another century, Italy for another 5 centuries, and Illyria almost a millennium.Of the many accepted dates for the end of the classical Roman state, the latest is 610. This is when the Emperor Heraclius made sweeping reforms, forever changing the face of the empire. Greek was readopted as the language of government and Latin influence waned. By 610, the Eastern Roman Empire had come under Greek influence and became what many modern historians now call the Byzantine Empire, although the Empire was never called thus by its inhabitants (rather it was called Romania, Basileia Romaion or Pragmata Romaion, meaning "Land of the Romans", "Kingdom of the Romans"), who still saw themselves as Romans, and their state as the rightful successor to the ancient empire of Rome. The sack of Constantinople at the hands of the Fourth Crusade in 1204 is sometimes used to date the end of Eastern Roman Empire: the destruction of Constantinople and most of its ancient treasures, total discontinuity of leadership, and the division of its lands into rival states with a Catholic-controlled "Emperor" in Constantinople itself (see Latin Empire) was a blow from which the Empire never fully recovered. Nevertheless, the Byzantines continued to call themselves Romans until their fall to Ottoman Turks in 1453. That year the eastern part of the Roman Empire was ultimately ended by the Fall of Constantinople. Even though Mehmed II, the conqueror of Constantinople, declared himself the Emperor of the Roman Empire (Caesar of Rome / Kayser-i Rum) in 1453, Constantine XI is usually considered the last Roman Emperor. The Greek ethnic self-descriptive name Roman survives to this day.