A conquest of Murcia took place in 1265–66 when James I of Aragon conquered the Muslim-held Taifa of Murcia on behalf of his ally Alfonso X of Castile.
Previously, Murcia was a semi-independent vassal of Castile, but renounced its allegiance during the Mudéjar revolt of 1264–1266. Aragon entered the war on Castile's side after Castile's Queen Violant—who was James' daughter—wrote a letter asking for her father's help.
After initial negotiations with his nobles, James marched from Valencia at the end of October 1265. Subsequently, Aragonese troops took multiple Murcian towns and defeated a reinforcement column sent by the Emirate of Granada. The siege of the city of Murcia started in January 1266, ending in its surrender on 31 January and James' entrance to the city on 3 February.
After the conquest, Murcia was returned to Castile and lost its semi-independent status. Subsequently, its Muslim population was moved to suburbs as Castile brought Christian settlers to populate the region.
Background
In the first half of the thirteenth century, Castile and Aragon conquered multiple Muslim states in southern Spain. Murcia, a major power centre in the southeast, surrendered on 2 April 1243 to Infante Alfonso, the future Alfonso X of Castile. After this conquest, the Taifa of Murcia became a semi-independent vassal of Castile, ruled by the Baha al-Dawla of Banu Hud. Under this arrangement, Murcia still had its own army, bureaucracy, and coins, but its rulers had to submit as Alfonso's vassals. Baha al-Dawla remained loyal to Alfonso X, despite his policy of supporting Murcia's Christian population. Baha al-Dawla was succeeded by his son, Abu Ja'far in 1259, who died after a few years and was replaced by his son Muhammad. Muhammad was soon deposed by his cousin Abu Bakr ibn Hud, also known as Al-Wathiq. By this time, Sultan Muhammad I of the neighboring Emirate of Granada had consolidated his power and territories to become another regional power, even though nominally also under Castile's sovereignty.
Rebellion
In late July or August 1264, the Muslim population ("Mudéjars") of Lower Andalusia started a rebellion against Castile, beginning in Jerez and spreading to other towns. The rebellion was partly caused by Castile's oppressive forcible relocation policy against the Muslims, as well as by instigation from Muhammad I of Granada. Muhammad I renounced his allegiance to Castile and attacked as well. Multiple settlements and castles, including Jerez itself, fell to the rebels or Granadan troops.
Murcia joined the rebellion as well. The Murcians expelled Castillian troops from its alcázar (castle), and al-Wathiq declared allegiance to Muhammad I. Muhammad I sent troops to help Murcia led by his Banu Ashqilula ally, Abdallah ibn Ali. Abdallah might have taken power in Murcia before the Murcians reinstated al-Wathiq at some point during rebellion.
Aragonese offensive
Preparation
Initially the task to suppress the revolt passed to Alfonso's brother Manuel and Grand Master Paio Peres Correia of the Order of Santiago. Concerned that Castile was fighting on three fronts, Alfonso X asked his wife, Queen Violant to request help from her father, James I of Aragon. James I agreed and summoned his parliaments to support the war. The Catalan Courts agreed to raise taxes for the campaign in July 1264, but the parliament for his other dominion, Aragonese Corts initially rejected the campaign when they met in November. James I spent the next following months trying to convince the Aragonese lords. In May 1265, the Archbishop of Tarragon and the Bishop of Valencia began preaching for crusades. Pope Clement IV allowed James to collect tithe from his dominions for up to three years to fund the crusade. Infante Peter (future Peter III of Aragon) carried out initial raids against the rebels in late summer of 1265.
Invasion of Murcia
James I marched with his troops from Valencia at the end of October 1265. He kept his army close together and advanced through Muslim-held towns. In turn, the Muslims of Villena, Elda, Petrer, Orihuela surrendered to him, with terms that they were allowed to keep their lands and worship freely.
James now prepared to march on the city of Murcia itself and was joined by Castilian troops under Infante Manuel. At the same time Granadan troops, numbering 800 cavalry and 2,000 men-at-arms, marched to relieve the city. James moved to intercept this column and the Granadans were routed in a battle.