Sancho (died 1223), also spelled Sanç or Sanche,[a] was a Catalano-Aragonese nobleman and statesman, the youngest son of Queen Petronilla of Aragon and Count Raymond Berengar IV of Barcelona.

[2] Sancho came of age between 1175, when he first began witnessing the royal charters of his eldest brother, King Alfonso II of Aragon, and 1180.

[4] On 9 December 1182, Alfonso visited his brother in Aix and exempted the Knights Hospitaller from commercial duties and tolls in Provence.

[6][7][8] Sancho's expense account for his stay at Perpignan in November 1184, where he met his brother, has survived and provides a detailed look at how his court functioned.

[1][11][12][8] These actions of disloyalty caused a rift between the brothers, and Alfonso dispossessed Sancho of Provence, Gévaudan, Rodez and Carlat.

[14] Alfonso was in Aix by March 1185, when the dating clause of a charter reads "when we recovered Provence from the hands of Sancho, our brother".

In 1209–10, Sancho left the day-to-day government in the hands of a "vicar and bailiff" (vicarius et baiulus), Ferran de Norvais.

Together they pursued a policy that favoured communal liberties and commercial activity while opposing encroaching French and Papal influence.

[11] His power base, however, was in Provence and he had limited support in Aragon and Catalonia, especially for his preferred policy of continuing the war against Simon de Montfort.

In order to prevent the county of Bigorre from falling out of Aragon's orbit, Sancho arranged for his son Nuño to marry Gaston's widow, the hereditary countess Petronilla, in 1215.

[21] In November 1215, Sancho sent two envoys, Pedro Ahones and Guillem IV de Cervera, to attend the Fourth Council of the Lateran in Rome as representatives of Aragon.

In a letter addressed to Pope Innocent III, Sancho had also requested enhanced authority as procurator, but the envoys returned instead with a series of orders dated 23 January 1216 in which Innocent appointed seven noblemen from both Aragon and Catalonia as deputy counsellors to assist Sancho and ordered all the men of the realm to observe the truce with the crusaders.

[21] On 12 June 1216 Sancho signed a treaty at Balaguer in Aragon with representatives of the rectors of the Confraternity of the Holy Spirit of Marseille, a pious lay association that was the de facto government of the city.

This treaty was a response to Petronilla of Bigorre's marriage to Guy de Montfort, which the viscount of Béarn considered a threatening move.

The newfound allies invaded Bigorre and as a result Simon de Montfort lifted his siege of Lourdes, temporarily removing the threat the crusade posed to western flank of the Aragonese sphere.

[21] Sancho's policy of intervention in Occitania was opposed by a faction of Aragonese nobles led by his nephew, Ferdinand, abbot of Montearagón, and by those who wished to make peace with the Papacy.

[21] In two bulls dated 28 and 29 December 1217,[22] Pope Honorius III threatened to excommunicate James and Sancho, respectively, and to authorise a crusade against their realm if they did not abandon Raymond VI's cause.

[22][25] Shortly after his resignation, in the same month of September 1218, Sancho was present at the assembly in Lleida, where he was named as one of the king's advisers when James confirmed the privileges of Montpellier, which he had inherited from his mother.