The Seventh Crusade (1248–1254) was the first of the two Crusades led by Louis IX of France. Also known as the Crusade of Louis IX to the Holy Land, it aimed to reclaim the Holy Land by attacking Egypt, the main seat of Muslim power in the Near East. The Crusade was conducted in response to setbacks in the Kingdom of Jerusalem, beginning with the loss of the Holy City in 1244, and was preached by Innocent IV in conjunction with a crusade against emperor Frederick II, Baltic rebellions and Mongol incursions. After initial success, the crusade ended in defeat, with most of the army – including the king – captured by the Muslims.

Following his release, Louis stayed in the Holy Land for four years, doing what he could towards the re-establishment of the kingdom. The struggle between the papacy and Holy Roman Empire paralyzed Europe, with few answering Louis' calls for help following his capture and ransoming. The one answer was the Shepherds’ Crusade, started to rescue the king and meeting with disaster. In 1254, Louis returned to France having concluded some important treaties. The second of Louis' Crusades was his equally unsuccessful 1270 expedition to Tunis, the Eighth Crusade, where he died of dysentery shortly after the campaign landed.

In the years that followed the Barons' Crusade, the Kingdom of Jerusalem and the Ayyubid dynasty were both beset by internal strife that ultimately proved disastrous for both. The loss of Jerusalem and defeat at Gaza in 1244 ultimately marked the collapse of Christian military power in the Holy Land and led to the rise of the Mamluk sultanate. It is against this backdrop that Louis IX of France and pope Innocent IV began the Seventh Crusade to recover Jerusalem.

The Barons' Crusade ended in 1241 with the Kingdom of Jerusalem at its largest since 1187 after the negotiations made by Theobald I of Navarre. When Richard of Cornwall completed his negotiations with the Muslims, he then secured the support of the influential family of John of Ibelin, the Old Lord of Beirut. Holy Roman Emperor Frederick II had been crowned as king in March 1229, and the Ibelins agreed to accept him as regent as long as Simon de Montfort were appointed bailli until Conrad II of Jerusalem was of age and could receive the kingdom. When Richard returned home on 3 May 1241, the kingdom, still based at Acre, seemed to be restored, but suffered from rejection of Frederick and general lack of any central authority.

While waiting for Frederick's answer to Richard's proposal, the barons kept the claim of Alice of Champagne in reserve. Richard Filangieri remained in Tyre while the various barons returned to their fiefs in Syria and Cyprus, and Philip of Montfort, lord of Tyre, remained in Acre. The Templars, unsatisfied with the treaty with Egypt, besieged the Hospitallers at Acre and Hebron in 1241, who, under grand master Pierre de Vieille-Brioude, had supported the treaty. An-Nasir Dā'ūd, a Hospitaller ally, responded by attacking Christian pilgrims and merchants. Taking revenge, the Templars sacked Nablus on 30 October 1242, burning the mosque and killing the native Christians. The Muslims were not unreasonable in their belief that peace with the Franks was impossible.

Some Hospitallers joined with Filangieri in a plot to turn Acre over to the imperialists. The Templars, Philip of Montfort, the Genoese and Venetians put an end to the coup attempt. The main body of Hospitallers, conducting military action at al-Marqab against Aleppo, returned and de Vieille-Brioude disavowed the plot. The city remained under Ibelin control, while Filangieri was recalled to Italy. On 5 June 1243, the High Court ruled that Alice and her current husband Ralph of Nesle were entitled to rule Jerusalem as regents for Conrad II until he could come to the kingdom. Tyre remained occupied by Richard's brother Lothair Filangieri. When Richard was forced back to the harbor by a storm, fell into the hands of the barons and Lothair had to surrender the citadel at Tyre on 10 July 1243 to save him. Balian of Ibelin was appointed royal custodian of Tyre and the lordship was eventually assigned to Philip of Montfort. Jerusalem was essentially a feudal republic administered by the most powerful barons.

After the recovery of Jerusalem and much of Galilee, the kingdom was unable to sufficiently reorganize to counter the threats from the Ayyubids and Mongols. The quarrels between imperialist followers of Frederick II and the Ibelins, between the Templars and Hospitallers, and Acre versus Tyre left the kingdom almost defenseless. The defeat of the imperialists left the Templars in a strong position, negotiating a treaty in 1243 with a coalition of the rulers of Homs, Kerak, and Damascus against Egypt that eased tensions and restored Temple Mount to the order. Grand master Armand de Périgord triumphantly reported the return of the Templars to their original home to the pope. While the treaty promised to enhance Frankish security in Syria, but would prove toothless in light of the impending onslaught.

Since the death of the sultan al-Kamil in 1238, the political situation in Egypt and the Levant was chaotic, stoked by rivalries between his sons. In early 1240, while making ready to invade Egypt, as-Salih Ayyub, the eldest son, was informed that his half-brother Al-Adil II, then sultan, was being held prisoner by his own soldiers. He was invited to come at once and assume the sultanate. In June 1240, he made a triumphal entry into Cairo and assumed rule of the dynasty. Once installed in Cairo, as-Salih was far from secure, as the dynasty and associated Kurdish clans had divided loyalties. Within Egypt, a powerful faction of emirs were conspiring to depose him and replace him with his uncle, as-Salih Ismail, who had regained control of Damascus. As-Salih took refuge in the Cairo citadel, no longer trusting even the once-loyal emirs who had brought him to power. Kipchak mercenaries became available following the Mongol invasion in central Asia and soon formed the core of his army known as Mamluks. Before the end of the Seventh Crusade, the Mamluks would eventually overthrow the Ayyubid dynasty and take power on their own.