In the year 1095, Pope Urban called for a new kind of war - the Crusades. This would be a holy war to take back Jerusalem from Muslim control. Four years later, and Jerusalem was indeed seized by crusader forces. At that time, the crusaders seemed unstoppable. But through the 12th century, the Islamic enemies of the invading Christian crusaders became more unified and took back lost territory. Talking Templars presenters Dr Steve Tibble and Tony McMahon look at whether the Crusades could have been successful for the Christian forces of were they always doomed to lose?