The city of Osca, present Huesca, had come to be called Washqah after the Arab conquest in the late eighth century, falling within the Tagr al-A'la, the Upper March of the Emirate of Córdoba.

It was ruled by a local governor appointed from Córdoba, but was repeatedly subject to political turmoil, rebellion and assassination as the Banu Qasi, Banu Amrus and Banu al-Tawil clans, as well as the Arista dynasty of Pamplona, struggled for control, autonomy or independence from the Emirate, later Caliphate.

In the mid-tenth century, Wasqah had been given to the Banu Tujibi, who governed the Upper March from Zaragoza, and it became part of their Taifa of Zaragoza when in 1018 they successfully freed themselves from the disintegrating Caliphate.

Sancho Ramirez had built the nearby Montearagón castle in 1094 with the intention of laying siege to Wasqah but had been killed by a stray arrow as he was reconnoitering the city's walls.

Peter had succeeded to the whole of his father's kingdom only on the latter's death while besieging Huesca in 1094.

Peter had raised the siege, only to return to it within the year.

After 1094, his objectives had shifted westwards, towards the valley of the Gallega.

In 1095, Peter had renewed his father's oaths to Urban II, and Urban renewed his promise of protection, under which Sancho, his sons, and his kingdom had been placed in July 1089.

On March 16, 1095 the pope had even issued a bull, Cum universis sancte, granting the king and queen of Aragon immunity from excommunication without the permission of the pope.

This same year, while he is besieging Huesca, Peter defeats the relief forces of the Taifa of Zaragoza at the Battle of Alcoraz.

Peter later rewards a certain Sancho Crispo for his contribution of three hundred knights and infantry at Alcoraz.

He goes on to take Huesca on November 27 of this same year.