Gregory VII, the Pope who issued the first call to "liberate" the Holy Land, had earlier supported William the Conqueror (a Norman) in his bid to rule England (which actually happened after the
Battle of Hastings in 1066). Later regretting his stance, the pope (in 1080) wrote to William (then King of England):
...with what zeal I laboured to advance you to your royal state. So much so that I had to bear from certain of my brethren the almost infamous charge of having lent my aid in bringing about so great a sacrifice of human life.
When medieval popes called for action, people responded. But Gregory VII was distracted by a feud with Henry IV of Germany, so the desire to "liberate" Jerusalem had to await a new Pope.
In 1095, Pope Urban II preached a sermon at the Council of Clermont. Responding to an urgent request for help from the Byzantine emperor, who wanted to regain territory he had lost to Muslim Turks, the pope summoned Christian men to make a pilgrimage to the Holy Land.
This time, "so great a sacrifice of human life" would hardly describe what was about to occur. This time, life in the ancient city of Jerusalem would change forever.