The experience of the Jewish people during the First Crusades, as with many historical periods characterized by marked increases in antisemitism, pogroms, and so on, demonstrated above all their commitment to their faith and their perserverence in enduring these periods of violent hostility.
Pope Urban II, envisioning the unification of the Roman Catholic and Greek Orthodox Churches, the latter increasingly threatened by the spread of Islam, inspired the launch of the First Crusade as a means of capturing Jerusalem. As a central tenet of the First Crusade was "saving" mankind from the tyranny of Hell, the Pope announced that the mission to save Jerusalem and cement Christianity was the path to redemption and Heaven. Consequently, every kind of European joined the Crusade, including many with less than beneficent characters or intentions. On the top of the list of nonbelievers who were to be cleansed from the Holy Land were the Jews, whose rejection of the teachings of Jesus, and alleged responsbility for the crucifixion of Christ were obviously highly anathema to the Church and its warriors.
Despite the torture and killing of Jews who refused to convert, the end of the First Crusade did not mean the end of the Jewish presence in Jerusalem and Greater Palestine. As many Arabs were converted to Christianity, Jews continued to hold fast to their religious beliefs.
While the First Crusade established the precedence for additional such missions by militant Christians, and while the Jewish presence in Palestine inevitably declined with their continued persecution, their religious and cultural ties to the land survived. What that Crusade illuminated about the Jewish people, then, is the strength of their conviction and the strength of their ties to the land on which Israel and much of the areas of Judea and Samaria sit. [Educator's Note: This is not intended as a political statement, but simply as a description of Jewish sentiments.]