Pierre II of Aragon , known as the Catholic , born v. 1174 - 1177, dead the September 12th 1213 with the Battle of Low wall, was king d' Aragon, count de Barcelone (under the name of Pierre Ier) and marquis de Provence of 1196 with 1213.

It was wire of Alphonse II Raimond '' Pure the '' (1152-1196), king d' Aragon and count de Barcelone, and of Sanchia de Castille

In 1204, it married Marie of Montpellier (v. 1181-1213), widow of Bernard IV of Comminges and girl of Guillaume VIII, lord of Montpellier, and Eudoxie Comnène (1162-apr. 1202). The two husbands separated quickly and Montpellierains had to resort to a subterfuge to lead to the design of infant it Jacques, future Jacques the Conqueror. This last remained the only child of the couple.

He recognized himself like vassal papacy and was crowned by the pope Innocent III with Rome in 1204, swearing to defend the catholic faith , which is at the origin of its nickname. He was first king d' Aragon to be crowned hands of sovereign pontiff. This recognition of pontifical suzerainty does not seem to be appreciated by all in Aragon.

It took part in the Bataille of Mow Navas de Tolosa in 1212, during which the Moors underwent a severe defeat.

The following year, it takes part in Albigensian Crusade while going to the help of its vassal and father of its brother-in-law Raymond VII (1197-1249), husband since 1211 of his sister Sanchia d' Aragon (v. 1186-apr. 1241), the count de Toulouse Raymond VI (1156-1222), but finds death at the time of the Bataille of Low wall the September 12th 1213, vis-a-vis the army of Simon IV of Montfort.

Pierre II of Aragon contributed to the diffusion in Spain of poetry of Provence.