Why would urban ii agree to help alexius?

Answer 1

Muslim armies had conquered much of northern Africa, Egypt, Palestine, Syria, and Spain, which had been some of the most heavily Christian areas in the world. Thousands, and possibly millions, of Christians died during this drive to eventually bring the entire world under Islam. The First Crusade was launched in 1095 by Pope Urban II to check the advance of the Muslims and regain control of the city of Jerusalem and the Holy Land. If this defensive war was not fought then we would probably all be Muslim today. I am sure that some atrocities were committed by individuals of both sides during this war but by most people's judgment this was a just war.

Answer 2

All of the history you have heard about the Crusades is so much hogwash, the Church had been trying to help the Christians who were being murdered and enslaved in the Holy Land for centuries but the Church was having its own problems, it wasn't until Pope Urban in the eleventh century, that the Church was finally able to come to their rescue.

from Seven Lies About Catholic History, by Diane Moczar

Unprovoked Muslim aggression in the seventh century brought large parts of the southern Byzantine Empire, including Syria, the Holy Land, and Egypt under Arab rule. Christians who survived the conquests found themselves subject to a special poll tax and discriminated against as an inferior class known as dhimmi. Often their churches were destroyed and other harsh conditions imposed. For centuries their complaints had been reaching Rome, but Europe was having its own Dark Age of massive invasion, and nothing could be done to relieve the plight of eastern Christians.

By the eleventh century, under the rule of a new Muslim dynasty, conditions worsened. The Church of the Holy Sepulcher, site of the Crucifixion was destroyed, along with a large number of other churches, and Christian pilgrims were massacred. In 1067 a group of seven thousand peaceful German pilgrims lost two-thirds of their number to Muslim assaults. By this time the popes, including St. Gregory VII, were actively trying to rally support for relief of eastern Christians, though without success. It was not until the very end of the century, in 1095, that Pope Urban's address at Clermont in France met with a response-though not quite the one he had hoped for.