Turkey itself was once the home of the Ottoman Empire which ruled vast territories upon three different continents. It was a world power that lasted from 1299 to 1923. At the height of its power, in the sixteenth and seventeenth centuries, the empire controlled much of Southeastern Europe, Western Asia and North Africa. The Ottoman Empire contained 29 provinces and numerous vassal states. Because the Ottoman Empire with its capital in Istanbul, the former Constantinople, had aliened itself with Germany and the axis powers during World War I, the Ottoman Empire was dismantled primarily by the British and the French. The Republic of Turkey was officially proclaimed on 29 October 1923.