The shores of the Bosphorus became the homeland to various civilizations throughout history , the Greeks from Megara in BC 685 years has grown to develop with the establishment of a city-state in the region today, the historical peninsula called . [5] Eastern Roman Empire and the capital of the Ottoman Empire and today the Republic of Turkey ' the icon is one of the largest city of Istanbul and the city's need , as well as being used as one of the chief elements in the promotion of the country abroad .