The Arabs began to win victories against the Byzantines and captured much of their richest land during the period 600- 1200; subsequently they was less money for the Byzantine emperors to spend on defence. At the same time the Byzantines faced threats from the Slavs and Bulgars to the north who regularly raided Byzantine territory, but were eventually more or less subdued. In 1204, following a dispute over payment to the fourth crusade in exchange for placing a usurper onto the throne of Byzantium (and due to Venice coveting Byzantine trading ports), the crusade sacked Constantinople and split its lands. The resultant states (Trebizond, Nicaea, and Epirus) were separate but had similar intentions; rid themselves of the crusaders and reconquer Constantinople. This effort, while eventually successful, allowed the Arabs/Turks to conquer yet more land and crippled what was left of the Byzantine economy. They were never again able to put up a good enough fight and the Ottomans gradually conquered/annexed land from the Empire, and in 1453 besieged and conquered Constantinople itself.
The best introduction to the topic would be John Haldon’s Byzantium: a History
The best introduction to the topic would be John Haldon’s Byzantium: a History
