The Byzantines were weakened by internal divisions, military defeats, and economic instability, which made them vulnerable to attacks by the Muslim armies. One of the key factors that made Byzantium susceptible to Muslim attacks was the prolonged conflict with the Sassanid Empire, which weakened both empires and left them vulnerable to external threats. Additionally, the Byzantine Empire suffered from a series of civil wars, internal strife, and political instability, which further weakened its defenses and ability to resist invasions. These factors made the Byzantines an easy target for the rapidly expanding Muslim armies, leading to the Arab conquests of the Levant, Egypt, and eventually the heart of the Byzantine Empire in Anatolia and Constantinople.
