The siege of Acre (also called the fall of Acre) took place in 1291 and resulted in the Crusaders' losing control of Acre to the Mamluk Sultanate of Egypt. It is considered one of the most important battles of the period. Although the crusading movement continued for several more centuries, the capture of the city marked the end of further crusades to the Levant. When Acre fell, the Crusaders lost their last major stronghold of the Crusader Kingdom of Jerusalem.
In 1187, Saladin conquered much of the Kingdom of Jerusalem (also called the Latin Kingdom), including Acre and Jerusalem, after winning the Battle of Hattin and inflicting heavy losses on the Crusaders. The Third Crusade was launched in response; the Crusaders besieged and eventually recaptured Acre in 1191. Acre became the capital of the Kingdom of Jerusalem. The religious orders made their headquarters in and around the city, and from there made crucial military and diplomatic decisions. For example, when the Mongols arrived from the East in the mid-13th century, the Christians saw them as potential allies.
In 1250, the Mamluk Sultanate arose in Egypt; it was a more dangerous enemy than the Ayyubids. The Mamluks fielded heavy cavalry – a match for the Crusader knights – and were much more hostile. The Crusaders initially attempted to maintain a cautious neutrality with the Mamluks. In 1260, the Barons of Acre granted the Mamluks safe passage through the Latin Kingdom en route to fighting the Mongols; the Mamluks subsequently won the pivotal Battle of Ain Jalut in Galilee against the Mongols. This was an example of atypically cordial relations between the Christians and the Mamluks.
However, as early as 1261, after the Battle of Ain Jalut, Sultan Baibars led the Mamluks against the Crusaders. Baibars captured Caesarea, Haifa, and Arsuf in 1265, all the important Crusader holdings in Galilee the following year, and then Antioch in 1268.
European states launched a number of minor Crusading expeditions to reinforce the Crusader states, including the abortive Crusade of Louis IX of France to Tunis in 1270, and the minor Ninth Crusade of Prince Edward (later King Edward I) of England in 1271–1272. The expeditions failed to provide the required relief; they were too small, too short-lived, and the interests of the participants were too diverse.
More seriously, no major reinforcing Crusade was forthcoming. Pope Gregory X was unable to rally support for another great Crusade. Papal advisors blamed the lack of enthusiasm to the laziness and vice of the European nobility and to clerical corruption. A more fundamental reason seems to have been the debasement of the Crusading ideal; Gregory X's predecessors had used Crusades to raise armies against the Papacy's European enemies, such as the Albigensian Crusade declared by Innocent III against the Cathars & a crusade against the Hohenstaufen Emperor Frederick II declared by Innocent IV.
The Crusader states continued to deteriorate from continuing attacks and political instability. In 1276, the unpopular "King of Jerusalem" Hugh III moved his court to Cyprus. Under Sultan Al-Mansur Qalawun, the Mamluks captured Lattakia in 1278, and conquered the County of Tripoli in 1289. Qalawun concluded a ten-year truce with the Kingdom of Jerusalem in 1284.
Following the fall of Tripoli, King Henry II, son of Hugh III, sent seneschal Jean de Grailly to warn European monarchs of the critical situation in the Levant. Pope Nicholas IV supported Jean by writing letters urging European potentates to act. However, the Sicilian question overshadowed calls for a new Crusade, and Edward I of England was too entangled by troubles at home.
Decades of communications between the Europeans and the Mongols failed to secure a meaningful Franco-Mongol alliance.
One Arab account claims that an affair between a rich young wife of the city and a Mussulman was discovered by the husband:
gathers together some friends goes out from Ptolemais [...] and immolates them both to his injured honour. Some Mussulmans are drawn to the spot, the Christians come up in still greater numbers, the quarrel becomes angry and general and every Mussulman is massacred.
The Crusaders feared that Qalawun would use this as a pretext to resume the war, and petitioned the pontiff for reinforcements. According to Michaud, 25 Venetian galleys carrying 1600 men "levied in haste in Italy" were sent. Other sources claim 20 galleys of peasants and unemployed townfolks from Tuscany and Lombardy, led by Nicholas Tiepolo, the son of Doge Lorenzo Tiepolo, who was assisted by the returning Jean de Grailly and Roux of Sully. These were joined by five galleys from King James II of Aragon who wished to help despite his conflict with the Pope and Venice.
The Italian reinforcements were ill-disciplined and without regular pay; they pillaged indiscriminately from both Muslims and Christians before setting out from Acre. According to Runciman they attacked and killed some Muslim merchants around Acre in August 1290, although in Michaud's account they instead pillaged and massacred towns and villages. Qalawun demanded the extradition of the Christian perpetrators. On the suggestion of Guillaume de Beaujeu, the Grand Master of the Knights Templar, the Council of Acre debated the issue; the Sultan's demand was rejected, with the Crusaders claiming that the murdered Muslims had been responsible for their own deaths.
Sultan Qalawun dissolved the truce with Acre, and the Mamluks began mobilizing by October 1290. Qalawun died in December and was succeeded by his son, Al-Ashraf Khalil (sometimes spelled Chalil). Guillaume de Beaujeu received a message from Khalil, which stated the latter's intention to attack Acre and to refuse peace overtures. Nonetheless, the Crusaders dispatched a peace delegation, led by Sir Philip Mainebeuf, to Cairo; the delegation was imprisoned. Khalil set out from Cairo in March 1291.
The assembled Mamluk army greatly outnumbered the Crusaders. Khalil called upon Syria to reinforce his Egyptian army; he was answered by contingents from Damascus (led by Lajin), Hama (led by al-Muzaffar Taqai ad-Din), Tripoli (led by Bilban) and al-Karak (led by Baibars al-Dewadar.) A significant portion of the troops were volunteers. The army included a substantial artillery train drawn from fortresses across the Mamluk empire. Hama sent the enormous catapult "The Victorious" (المنصورى). Another large catapult was "The Furious" (الغاضبة). There were also lighter mangonels called "the Black Bulls" (الثيران السوداء).
Notable historians in the Mamluks' ranks included Baybars al-Dewadar, and Abulfeda in the Haman contingent.
The Crusaders' appeals for aid met with little success. England sent a few knights, including Otto de Grandson of Savoy. The only noteworthy reinforcements came from Henry II of Cyprus, who fortified the walls and sent troops led by his brother Amalric, Lord of Tyre. Burchard von Schwanden suddenly resigned as Grand Master of the Teutonic Order and left Acre for Europe; he was succeeded by Konrad von Feuchtwangen. The only major contingent to leave were the Genoese, who concluded a separate treaty with Khalil. Many women and children were evacuated from Acre to Cyprus in March.
Acre was defended by an inner and outer wall, with a total of twelve towers built by European kings and rich pilgrims.