They ruled for over 500 years but gradually their power waned and they remained only symbolic rulers bestowing legitimacy upon various sultans and princes who wielded actual military power. The Abbasid caliphate was finally abolished when Hulagu, the Mongol ruler, captured Baghdad in 1258, destroying much of the city including its incomparable libraries.
While the Abbasids ruled in Baghdad, a number of powerful dynasties such as the Fatimids, Ayyubids and Mamluks held power in Egypt, Syria and Palestine. The most important event in this area as far as the relation between Islam and the Western world was concerned was the series of Crusades declared by the Pope and espoused by various European kings. The purpose, although political, was outwardly to recapture the Holy Land and especially Jerusalem for Christianity.
Although there was at the beginning some success and local European rule was set up in parts of Syria and Palestine, Muslims finally prevailed and in 1187 Saladin, the great Muslim leader, recaptured Jerusalem and defeated the Crusaders.