In 1238, King James I of Aragon, with an army composed of Aragonese, Catalans, Navarrese and crusaders from the Order of Calatrava, laid siege to Valencia and on 28 September obtained a surrender. Fifty thousand Moors were forced to leave. Poets such as Ibn al-Abbar and Ibn Amira mourned this exile from their beloved Valencia. After the Christian victory and the expulsion of the Muslim population the city was divided between those who had participated in the conquest, according to the testimony in the Llibre del Repartiment (Book of Distribution). James I granted the city new charters of law, the Furs of Valencia, which later were extended to the whole kingdom of Valencia. Thenceforth the city entered a new historical stage in which a new society and a new language developed, forming the basis of the character of the Valencian people as they are known today.
Try to answer this question if possible (otherwise reply "unanswerable"): What ruler attacked Valencia in 1238?
King James I of Aragon