Final answer:
The defeat at Manzikert in 1071 led the Byzantine Empire to seek aid from the papacy, precipitating the Crusades as an unexpected outcome of Pope Urban II's call to arms. This marked a turning point in Christian-Islamic relations and set the stage for the ultimate fall of the Byzantine Empire to the Ottoman Turks in 1453.
Step-by-step explanation:
The defeat of the Byzantines at Manzikert by the Seljuks in 1071 significantly impacted the Byzantine Empire. This military loss exacerbated issues within the empire, leading to internal conflicts and the deposition and assassination of Emperor Romanos. As a result, the Byzantine rulers faced a period of instability. One of Romanos's successors, Alexios I Komnenos, sought assistance from the papacy, which led to Pope Urban II framing the conflict as a religious war, ultimately sparking the crusading movement. This call to arms by the church aimed to provide military support to the Byzantine Empire against the Seljuk Turks marked the beginning of the Crusades.
In subsequent years, the Byzantines continued to battle against Turkic powers, including facing sieges and assaults by the Ottoman Empire. Despite seeking aid from Christian powers in Europe and the Papacy, the empire experienced fluctuating fortunes. The Byzantine plea for assistance, influenced by the ongoing threat from the Turks, plays a prominent role in shaping the Christian-Islamic relations of that era. Although the empire endured after Manzikert, it remained in a frail state up until its conquest by the Ottoman Turks in 1453, which marked the end of the Byzantine Empire.