The Ottoman Empire had been one of the major facts in European history since the Middle Ages. By 1914 it had been much reduced, but still remained after Russia the largest European state. Stretching from the Adriatic to the Indian Ocean, the Empire was both a great political entity and a religious one, with the Sultan ruling over the Holy Sites and, as Caliph, the successor to Mohammed. Yet the Empire's fateful decision to support Germany and Austria-Hungary in 1914, despite its successfully defending itself for much of the war, doomed it to disaster, breaking it up into a series of European colonies and what emerged as an independent Saudi Arabia.