Lord Edward's crusade, sometimes called the Ninth Crusade, was a military expedition to the Holy Land under the command of Edward, Duke of Gascony (future King Edward I of England) in 1271–1272. It was an extension of the Eighth Crusade and was the last of the Crusades to reach the Holy Land before the fall of Acre in 1291 brought an end to the permanent crusader presence there.
The Ninth Crusade saw Edward clash with the Mamluk sultan Baibars, with both achieving limited victories. The Crusaders were ultimately forced to withdraw since Edward had pressing concerns at home and felt unable to resolve the internal conflicts within the remnant Outremer territories. It is arguable that the Crusading spirit was nearly "extinct" by this period as well. It also foreshadowed the imminent collapse of the last remaining crusader strongholds along the Mediterranean coast.
Following the Mamluk victory over the Mongols in 1260 at the Battle of Ain Jalut by Qutuz and his general Baibars, Qutuz was assassinated, leaving Baibars to claim the sultanate for himself. As Sultan, Baibars proceeded to attack the Christian crusaders at Arsuf, Atlit, Haifa, Safad, Jaffa, Ascalon, and Caesarea. As the Crusader fortress cities fell one by one, the Christians sought help from Europe, but assistance was slow in coming.
In 1268, Baibars captured Antioch, thereby destroying the last remnant of the Principality of Antioch, securing the Mamluk northern front and threatening the small Crusader County of Tripoli. With royal and papal approval, Edward "took the cross" on 24 June 1268. Louis IX of France organized a large crusader army with the intent of attacking Egypt, but diverted it instead to Tunis. Louis himself died there in 1270. He had loaned Edward 70,000 livres tournois for his crusade.
Edward and his brother Edmund prepared an expedition to join Louis at Tunis, but it was delayed several times in the summer of 1270 because their father, King Henry III of England, could not make up his mind whether to join it or not.