The Byzantine Empire was defeated by the Ottoman Empire in 1453. The Ottoman Empire was a powerful Muslim state that had been expanding its territory for centuries. In 1453, the Ottoman sultan, Mehmed II, led an army of over 100,000 soldiers to besiege Constantinople, the capital of the Byzantine Empire. The Byzantines were outnumbered and outgunned, and after a two-month siege, the city fell to the Ottomans. The fall of Constantinople marked the end of the Byzantine Empire and the beginning of the Ottoman Empire's dominance over the region.