The siege of Jerez by King Alfonso X of Castile took place in 1261 (in A.H. 659 [6 December 1260–25 November 1261], according to Ibn ʿIdhārī), presumably in the late spring or early summer.
[1] At the time of the siege, Jerez was one of several autonomous Muslim enclaves left over after the collapse of Ibn Hud's principality and the successful reconquista campaigns of Alfonso's father, Ferdinand III.
[1] According to the Chronicle of Alfonso X, which erroneously compresses the events of 1253 and 1261 into the year 1255, the king told the assembly that he desired "to serve God by doing harm to the Moors [and] to seize their lands, especially those near the city of Seville.
The latter was chosen because of its strategic importance to the landward defence of the newly developed port of El Puerto de Santa María.
It is probable that the cortes authorised a tax to pay for both the campaign against Jerez and the one to follow against Niebla, since Alfonso was still collecting arrears fifteen years later.