The most extraordinary siege in medieval history began with the arrival of a Christian army at Jerusalem on the dawn of 6 June 1099. There were other sieges that lasted longer, involved greater numbers of troops and deployed more siege engines, but nothing else in the entire medieval period compares to the extraordinary journey that the besiegers had made to get to their goal and the heady religious enthusiasm among the troops. This was the culmination of the First Crusade, a military pilgrimage that had seen hundreds of thousands of men, women and children leave their homes in Western Europe,