March 20, 1915
The British government signed a secret agreement with Russia regarding the hypothetical post-World War I division of the former Ottoman Empire. By the terms of the agreement, Russia would annex Constantinople (now called Istanbul), the Bosporus Strait (a waterway connecting the Black Sea with the Sea of Marmara and marking the boundary between the Asian and European halves of Turkey), and more than half of the European section of Turkey. Britain also promised Russia future control of the Dardanelles Strait and the Gallipoli peninsula. In return, Russia would agree to British claims on other areas of the former Ottoman Empire and central Persia, including the oil-rich region of Mesopotamia (now Iraq.)
