successes; but finding himself betrayed and deserted by the Palestinian barons, he returned home in the following year. But the Germans under Leopold VII. of Austria, who had accompanied him remained, and, supported by a Cologne and Dutch fleet, undertook in A.D. 1218, along with the titular king John of Jerusalem, a crusade =against Egypt=. Damietta was taken, but the overflow of the Nile reservoirs placed them in such peril that they owed their escape in A.D. 1221 only to the generosity of the Sultan Camel. § 94.5. =The Fifth Crusade, A.D. 1228.=--The Emperor Frederick II. had promised to undertake a crusade, but continued to make so many excuses for delay that Gregory IX. (§ 96, 19) at last thundered against him the long threatened excommunication. Frederick now brought out a comparatively small crusading force. The Sultan Camel of Egypt, engaged in war with his nephew, and fearing that Frederick might attach himself to the enemy, freely granted him a large tract of the Holy Land. At the Holy Sepulchre Frederick placed the crown of Jerusalem, the inheritance of his new wife Iolanthe, with his own hands on his head, since no bishop would perform the coronation nor even a priest read the mass service for the excommunicated king. He then returned home in A.D. 1229 to arrange his differences with the pope. The crusading armies which Theobald, king of Navarre, in A.D. 1239, and Richard Earl of Cornwall, in A.D. 1240, led against Palestine, owing to disunion among themselves and quarrels among the Syrian Christians, could accomplish nothing.