Page "Bosphorus" Paragraph 12

The strategic significance of the strait was one of the factors in the decision of the Roman Emperor Constantine the Great to found there in AD 330 his new capital, Constantinople, which came to be known as the capital of the Eastern Roman Empire.

On 29 May 1453 it was conquered by the emerging Ottoman Empire.

In fact, as the Ottoman Turks closed in on Constantinople, they constructed a fortification on each side of the strait, Anadoluhisarı ( 1393 ) and Rumelihisarı ( 1451 ).