when did the byzantine empire start to decline
Decline of the Byzantine Empire But in the High Middle Ages, under pressure from the Seljuk Empire, it suffered serious setbacks and fell into decline. After the Battle of Manzikert (1071) it lost control of Anatolia, and while the Komnenos dynasty restored a degree of stability in the 12th century with help from the First Crusade, the empire was captured and partitioned by the Crusaders themselves in the Fourth Crusade in 1204.