Fourth Crusade. The initial goal was the capture of Jerusalem but the invaders ended up instead invading Constantinople, the capital of the Byzantine empire (now Istanbul). Constantinople was seized at the end of of the Fourth Crusade, largely thanks to the political maneuvering of Doge Enrico Dandolo. As a result of the crusade, Venice controls the entire Eastern Adriatic. Venice also buys Crete from Boniface of Montferrat, leader of the crusade, thus ensuring that Venice controls the trade route to Constantinople and Asia Minor. As its part of the looting of Constantinople, Venice brings back the four horses that stand over the entrance of St. Mark’s Basilica. Image: Conquest of Constantinople By The Crusaders In 1204 (15th-century miniature). This work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 70 years or less.