Istanbul Istanbul Istanbul (, or or ; ), historically known as Byzantium and before 1924 as Constantinople, is the most populous city in Turkey and the country's economic, cultural, and historic center. Istanbul is a transcontinental city in Eurasia, straddling the Bosporus strait (which separates Europe and Asia) between the Sea of Marmara and the Black Sea. Its commercial and historical center lies on the European side and about a third of its population lives on the Asian side. The city is the administrative center of the Istanbul Metropolitan Municipality (coterminous with Istanbul Province), both hosting a population of around 15
Istanbul Islam") was sometimes colloquially used to refer to the city, and was even engraved on some Ottoman coins, but the belief that it was the precursor to the present name, "İstanbul", is belied by the fact that the latter existed well before the former and even predates the Ottoman conquest of the city. The name "İstanbul" (, colloquially ) is commonly held to derive from the Medieval Greek phrase (pronounced ), which means "to the city" and is how Constantinople was referred to by the local Greeks. This reflected its status as the only major city in the vicinity. The