Why did Alexius Commenus ask Pope Urban 2 for help?

Alexius Comnenus, the Byzantine Emperor, sought help from Pope Urban II in 1095 due to the threat posed by Turkic tribes, particularly the Seljuk Turks, who were invading and conquering parts of the Byzantine Empire. He hoped to regain lost territories and strengthen his position by appealing to the Pope for military assistance. This request ultimately contributed to the launch of the First Crusade, as Urban II saw it as an opportunity to unite Christendom against a common enemy and reclaim the Holy Land.