The fourth century witnessed the split of the Roman Empire into two distinct empires: the Eastern Roman Empire (later called the Byzantine Empire) and Western Roman Empire , a split reinforced when
I transferred the capital of the Eastern Empire from Nicomedia (in Anatolia) to
(the city which inspired his imagination in 330 AD to be rebuilt as Nuova Roma (New Rome) ) . After Constantine's death , Byzantium had been called Constantinople ('City of Constantine') , until it fell under the Ottoman Empire on May 29 , 1453 , by then the Turks named it 'Istanbul' .
The Byzantine Empire had an evident character of Greco-Roman civilization . Significantly , when the Byzantines gradually embraced Christianity , during the 5th and 6th centuries , their culture acquired a noticeably distinct character , different from their pagan past . By the 7th century , the empire was channeled into another direction under the rule of Emperor Heraclius , when Greek was made the official language of the empire and improvements were made within the military . When its links with the old Greco-Roman world scattered , the Byzantine Empire finally started to acquire an 'Oriental' style , a style considerably strengthened by the 15th century , after the fall of Constantinople under the Ottoman Turks in the wake
of a long state of deterioration that had struck the Byzantine Empire in the 12th century .
Even when struck with recurrent setbacks , the Byzantine Empire eagerly preserved its economic , cultural and military position inside the continent through providing a military shield against early Muslim expansion; supplying the Mediterranean area with gold currencies; and imposing its influence on the political systems , laws , and customs of Europe , an influence which further spread into North Africa and the Near East for much of the Middle Ages .