The Sixth Crusade was one of the most successful of the Crusades, but took place against the wishes of the Pope - thereby not making it a true Crusade at all. It took place from 1228 until 1229 and was led by Frederick II. The successes of the Sixth Crusade came mainly from diplomacy, and achieved Jerusalem and south Palestine. However, the diplomatic agreement broke down and Jerusalem was lost in 1244 at the battle of Gaza. Research Sixth Crusade