Muslims were harassing Christians in the Holy Land.
The Muslim Seljuk Empire was conquering Anatolia at the time Pope Urban II sent the letter, in 1095, and posing a danger to the Byzantine Empire's eastern frontier. The Byzantines, who were Orthodox Christians, asked the Catholic pope for assistance because they were worried that the Seljuks may take control of their city, Constantinople. Additionally, the persecution of European trade caravans searching for eastern spices and Christian pilgrims to the Holy Land by Turkish Seljuk armies in Anatolia caused the Christian Europeans concern.
Pope Urban II regarded this as a chance to put a stop to feuds between European kingdoms and to extend the reach of his political influence. He thus urged every Christian to come together in holy land.
The Legislative Branch is the most powerful branch of the United States government not only because of the powers given to them by the Constitution, but also the implied powers that Congress has.
