During the Siege of Jerusalem, at the conclusion of the First Crusade in 1099, a priest led devotions on the Mount of Olives, attended by hundreds of Crusaders. After the Christian armies had captured the city, a thanksgiving procession to the Church of the Holy Sepulchre took place, attended by dozens of priests. In the interim, the Crusaders had murdered thousands of Muslims and Jews.

It is hard to understand how an army marching under the banner of the Cross could act thus. Yet throughout history we are confronted with the unsettling spectacle of Christians who behaved in ways dramatically at odds with the truths of the Gospel.