The Fourth Crusade (1202–1204) was a Latin Christian armed expedition called by Pope Innocent III. The stated intent of the expedition was to recapture the Muslim-controlled city of Jerusalem, by first defeating the powerful Egyptian Ayyubid Sultanate, the strongest Muslim state of the time. However, a sequence of economic and political events culminated in the Crusader army's 1202 siege of Zara and the 1204 sack of Constantinople, the capital of the Greek Christian-controlled Byzantine Empire, rather than Egypt as originally planned. This led to the partitioning of the Byzantine Empire by the Crusaders.