Unlike that of Mallorca, the Conquest of Valencia by King James I was achieved with the help of an important contingent from Aragon. In fact, in 1231 James I met with the nobleman Blasco de Alagón and the leader of the Military Order of the Hospital in Alcañiz to forge a battle plan for the conquest of Valencian territory.

Although Blasco de Alagón advised besieging the towns on fl at ground and avoiding the fortifi cations, thus taking advantage of the weakness of its Moorish government, the fi rst conquest was that of the mountainous enclave of Morella in 1232; and later of Ares, a town near to Morella, taken by James I to force Blasco de Alagón into handing Morella over.

The conquest of the kingdom of Valencia took place in three phases. It began in 1232, following an agreement made by the Courts of Monzón that year. Two years after new Courts that also met in Monzón decided to renew the advance, the city of Valencia surrendered, in 1238. The fertile plains of Valencia were repopulated by both the Catalans and the Aragonese.

The conquest of the south of the kingdom, that is, the third stage, was concluded with the capture of Biar in 1245. Although the nobility that had joined forces with the monarchy during the conquest pushed for Valencia to become simply an extension of Aragon, James I gave the new kingdom its own laws and institutions.

In both Mallorca and Valencia, James I decided to create kingdoms that were autonomous, while remaining part of the Crown of Aragon. In this way, his lands were divided into separate pieces which, to secure their heritage, James I divided among his sons in successive wills.