During the fourth crusade, the crusaders were diverted from fighting Muslims to fighting Christians. After helping Venetian merchants defeat their Byzantine trade rivals in 1204, crusaders captured and looted Constantinople, the Byzantine capital. In doing so, they left Christians in the holy land to fend for themselves. Muslim armies, meanwhile, overran the crusader states. By 1291, they captured the last Christian outpost, the port city of Acre. As in Jerusalem 200 years earlier, the victors massacred their defeated enemies. This time, the victims were Christians.
