The implementation of what became known as the Fifth Crusade (1217–1221) fell to Innocent III’s successor, Honorius III. He was an able administrator, mature, somewhat cautious, but deeply dedicated to both the crusade and the reform of the church. Honorius moved quickly to keep the crusade on its schedule. He also made increasingly clear that he was looking to Frederick II to play a leading role in it. But Frederick continued to be preoccupied in Germany, where the supporters of Otto IV remained active. The crusaders from the Rhineland and the Low Countries were ready to leave in 1217, as were some of the English, but Frederick was not. Nor were many of the French crusaders. King Andrew II of Hungary and Duke Leopold VI of Austria moved east- ward in August 1217. Some of the Rhenish contingent delayed in Portugal to assist in the capture of Alcácer do Sal. The crusade armies were to meet at Acre in Palestine.

Andrew of Hungary arrived first and conducted a sweep through the area around Lake Tiberias before returning home. Other crusaders laid siege to the Muslim fortifications on Mount Tabor, southwest of Tiberias. They were not able to vanquish the Muslim forces, but after their withdrawal the Muslims left Mount Tabor and retired to Nablus. The crusaders also strengthened fortifications along the coast in Caesarea and Château Pelerin (‘Athlit). Although these operations have been criticized, they were probably necessary to ensure the security of the Frankish settlements while the crusade moved against its main objective, Egypt. Thus, the Fifth Crusade picked up on the task left undone by the Fourth Crusade.

As the main forces gathered, still without Frederick, the crusaders selected as their leader the king of Jerusalem, John of Brienne. They moved to the Damietta mouth of the Nile to begin the siege of this important port, the gateway to Egypt, as it was known. In September 1218 the papal legate, Cardinal Pelagius of Albano, arrived, followed by a large body of French crusaders. The attack on Damietta was made more difficult by a chain that stretched from the city wall to a tower near the opposite side of the river and blocked passage upriver. The historian Oliver of Paderborn planned and directed the building of siege machinery on two boats that enabled the crusaders to take the tower. The sultan of Egypt, al-Ādil, brother of Saladin, is said to have died of shock at the news. He was succeeded by his son al-Kãmil. The capture of the Chain Tower enabled the crusaders to cross the Nile and lay siege to Damietta, while the new sultan consolidated his position. The Egyptians offered to surrender Jerusalem and other sites in return for the end of the siege. The crusade leadership was divided, but Cardinal Pelagius and the heads of the military orders pointed out that Jerusalem was indefensible without the possession of key fortresses in Transjordan. Damietta fell on 4 November 1219, and by the end of the month, the crusaders con- trolled most of the eastern Nile Delta.

Still Frederick had not arrived. He sought postponements from the pope while negotiations regarding his coronation as Holy Roman Emperor dragged on. He was determined to secure his rights before embarking on the crusade. Pope Honorius granted the postponements in the interest of the crusade, but events began to outrun the pace of the negotiations. After Frederick was crowned in Rome in November 1220, he entered his kingdom of Sicily and began to put matters there back into order. He had been in Germany for almost eight years. Many have criticized Frederick for his failure to go on crusade and Honorius for his laxity in pressing Frederick to fulfill his vow. Yet the problems that detained Frederick were real and weighty from his point of view, and Honorius was anxious to secure full cooperation. Neither could have anticipated what would eventually happen in Egypt. In fact, both tried to forestall just that kind of outcome. But events on the ground in the East could hardly be expected to wait on decisions in the West. King John left the crusader camp to meet what he regarded as a threat to the Latin kingdom from Syria as well as to pursue a personal claim to the Armenian throne. Pelagius was placed in a difficult position as the demand for action by rank-and-file crusaders mounted, which increased with the arrival of substantial reinforcements with Duke Ludwig I of Bavaria, the official representative of Emperor Frederick. In an attempt to placate those who wanted action, Pelagius and the duke decided to order a limited advance. They were joined shortly afterward by King John. But once begun, the advance became victim to its own success and, against the advice of John, moved toward Mansurah (mod. El- Mansûra, Egypt) at the point where a canal entered the Nile from the East. The Egyptians, reinforced by al-Kãmil’s brothers, cut the crusaders’ line of retreat and forced their surrender. In return for the surrender of Damietta, the crusaders were permitted to withdraw from Egypt. The Fifth Crusade had failed.

The blame for this defeat was shared by Frederick and the pope. Cardinal Pelagius has come under fire as well. But the failure of the Fifth Crusade chiefly illustrates the problem of conducting large-scale land operations far removed from western Europe. The immediate result of this defeat, however, was the determination by the pope to persuade Frederick to fulfill his vow. A marriage was arranged between Frederick and the young heiress to the Latin kingdom, Isabella II, the daughter of John of Brienne and Maria la Marquise. Frederick renewed his pledge to go on crusade, but before he was able to depart, Honorius died, in March 1227. The new pope was Cardinal Hugolino of Ostia, who took the name Gregory IX. When Frederick finally set out from Brindisi for the East in August 1227, there was an expectation that things would be different. But illness forced the emperor to turn back almost immediately. Gregory imposed the sentence of excommunication that had been agreed to by Frederick as part of the Treaty of San Germano in 1225.

Frederick, however, was determined to go on crusade. He now had a vital stake in the East from the fact that he was, through marriage, king of Jerusalem. Moreover, he had hopes of securing a treaty from al-Kãmil that would return Jerusalem and other holy sites to the Christians. It was, in fact, very close to the agreement that had been offered and rejected during the Fifth Crusade. But al-Kãmil had his eye on Syria, ruled by his brother, al-Mu‘azzam. Even after al-Mu‘azzam’s death, Frederick continued to push for an agreement.

When Frederick crossed to the East in June 1228, he once again demonstrated his strong determination to ensure what he regarded as his rights. Despite having few men and little money, he was able to secure the treaty, and on 17 March he entered Jerusalem. The treaty was denounced by Gerold of Lausanne, the Latin patriarch of Jerusalem, on the grounds that it provided no security for the city and left the lands of the patriarch and the Church of the Holy Sepulchre, on which they depended for income, in Muslim hands. Frederick’s calculations were further upset by events in Italy, where Pope Gregory IX ordered an attack on the kingdom of Sicily, apparently in reprisal for the seizure of the March of Ancona by Rainald of Urslingen, duke of Spoleto, who had been a source of friction between the papacy and the emperor for some time. Frederick returned to Italy, where he defeated the papal forces. By the Treaty of Ceprano (1230), Frederick and the pope resolved their immediate differences. Frederick’s achievement by his crusade was accepted, even if not welcomed.

There followed almost a decade of cooperation between pope and emperor. During this period, Frederick’s representatives in the Latin kingdom attempted to dominate the politics that swirled around the various noble factions. Frederick himself was occupied with affairs in Sicily and Germany. In the East, Cypriot nobles led by John of Ibelin, the lord of Beirut, carried on a struggle against the imperial lieutenants that ended in the lieutenants’ defeat in 1233. Likewise, on the mainland imperial administrators acting for Frederick as guardian of his son Conrad IV fared no better, though they held out until 1243 (the War of the Lombards). The only significant crusade in this period was led by Count Thibaud IV of Champagne in 1240, but it ended with only minor gains. With the expiration of Frederick’s treaty with al-Kãmil, the Ayyûbids moved to occupy Jerusalem. With the loss of the city, the crusades entered a new phase.

Hopes for the recovery of Jerusalem were now vested in the king of France, Louis IX. The Capetian kings of France had a tradition of crusading, but they were also known as hardheaded and practical men of affairs. The leading French historian of Louis IX, Jean Richard, has argued that he did not make a decision to go on crusade without overcoming a certain reluctance on his own part as well as the opposition of his mother, Blanche of Castile. What decided him was a serious illness that nearly cost him his life. Once determined, he set himself to the task with great energy. He entrusted the government of the kingdom to his mother and devoted himself to raising the required funds and making the necessary preparations. Although he worked with the pope, Innocent IV, the entire initiative was in his hands. The thoroughness of his preparations is demonstrated by the fact that he improved the Mediterranean port of Aigues-Mortes to serve as a point of departure and made arrangements for supplies to be stored in Cyprus. His objective was Egypt, and specifically the same port of Damietta that had been attacked by the Fifth Crusade.

Although Louis’s crusade was preached in various countries, it remained a French enterprise. Louis’s army was not large, but it was quite respectable in medieval terms. Louis spent about six times his annual income on the crusade, but most of the money came from non-royal sources. He left for the East on 25 August and landed near Damietta on 5 October, meeting almost no opposition. The garrison of the city fled, leaving it open to him. He immediately took over the city and made preparations to move inland. Some thought was given to the capture of Alexandria, but this was rejected in favor of an attack aimed at Cairo. On 20 November Louis moved south along the east bank of the Nile toward Mansurah. There the army stalled, unable to cross the canal that lay in its path, until a secret crossing place was made known to them. The king’s brother Robert of Artois led an advance guard across the canal but rashly attacked the Muslim camp. Louis, who crossed to aid his brother with the bulk of the army, was stymied by the arrival of the Ayyûbid sultan with reinforcements. Forced to retreat, he suffered heavy losses and had to surrender. Louis was ransomed, but Damietta was once more returned to the Egyptians. Louis left for Acre, where he devoted himself to improving the coastal fortifications of the Latin kingdom.

Perhaps more than any previous crusade, Louis’s expedition showed the magnitude of the task confronting those who desired to liberate the Holy Land. When the king returned home in 1254, he had accomplished little more than repairing some of the damage resultant from his failure at Damietta. He had not, however, lost his sense of commitment to the crusade, which, if anything, had been reinforced by the increasing depth of his personal piety.

The second half of the thirteenth century continued the story of military decline in the Latin states of Outremer. There were various efforts to provide support. Among the most important efforts was King Louis IX’s second crusade, launched on 2 July 1270. It was an impressive force. Lord Edward—the future King Edward I and son of Henry III of England—was due to join Louis. Although the goal of the crusade was to aid the Latin East, Louis had decided first of all to land at Tunis in North Africa. This landing was not, as some have thought, part of a plot against Tunis by Charles I of Anjou, the king’s brother, but the result of Louis’s belief that the ruler of Tunis was prepared to accept the Christian faith. But soon after the landing, dysentery swept through the camp. The king was one of its prominent victims and died from its effects. Edward, who arrived just as the crusaders were preparing to leave, continued to the East, where he conducted a limited campaign.

The second crusade of Louis IX was the last major crusade of the thirteenth century. Pope Gregory X, who had been elected pope while in Acre, worked zealously to promote the crusade to the East. On his instructions, the Dominican master general Humbert of Romans conducted an extensive survey to determine the depth of support for the crusade. At the Second Council of Lyons in 1274, Gregory issued a crusade document that not only codified previous experience but drew on the materials gathered by Humbert and others. His efforts bore fruit when the leading rulers of Europe took the cross, but the projected crusade did not get off the ground before the pope died in 1276. Thereafter, despite a growing awareness of the perils facing Outremer, no major crusade was mounted prior to the fall of Acre in 1291 to the Mamlûks of Egypt. The Mamlûk victory at Acre was the culmination of a Muslim resurgence that had begun shortly after the First Crusade of King Louis IX, when the Mamlûks, military slaves who formed an elite guard in Egypt, overthrew the Ayyûbid sultan and took control of the government. The military state that they created directed its external energies against the Franks as part of its effort to prove its legitimacy. By August 1291 the Franks no longer had a toehold on the Palestinian mainland. Still, they were a power in the region by reason of their possession of the kingdom of Cyprus and the naval power of the Western maritime cities, as well as by virtue of the military and financial support afforded by the military orders.