Answer:
The Byzantine emperor asked for help from the pope to defend his realm from the Seljuk Turks.
Explanation:
One of the reasons is that the Byzantine Empire had weakened considerably, and to help protect their borders, the Byzantium Emperor asked for help from the west to keep the Islamists from continuing to expand. Jerusalem was set as the goal, partly because of it's major role in Christianity, but in reality it was just to ask Western Europe to keep Islam from expanding and impeding into the Byzantium Empire's realm.
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