When Sancha finally returned to Aragon she entered the convent
Santa María of
Santa Cruz de la Serós, the oldest house of nuns in Aragon, founded in 922. Her sister Urraca was already a nun there, having entered at their father's request in 1061. Her other sister, Theresa, later also entered the monastery, probably on her brother Sancho's orders because no suitable husband could be found for her. Sancha does not appear to have become a nun, but to have instead acted as administrator of the convent. She was a beneficiary of her brother's donations, and her estates formed almost an
apanage (
infantazgo) of the royal family. They would form the nucleus of the monastery's later territory. On 27 October 1070 in the atrium of the abbey of Santa Cruz, before the abbess and the nuns,
Sancha de Aibar, the mother of King Ramiro, gave to her granddaughter and namesake, Countess Sancha, the monastery of
Santa Cecilia de Aibar with its appurtenances and revenues, the Villa Miranda in the
Cinco Villas and the estate of
San Pelayo de Atés. The elder Sancha had received the estate at Aibar with the monastery from Queen
Jimena Fernández, the grandmother of Ramiro. From Ramiro her son she received Miranda and San Pelayo after he became king. After her gift to her granddaughter she entered the convent of Santa Cruz. The younger Sancha was to enjoy the profits of her acquisitions until her own death, when they would pass to Santa Cruz. This donation and its stipulations is evidence that Sancha, although quite young, had no intention of remarrying as of 1070. In 1078, Sancha, acting on behalf of Santa Cruz, exchanged some land with the
monastery of Leire. In 1079, she made a similar exchange of properties with
San Juan de la Peña, this time accompanied by the abbess of Santa Cruz, Mindonia. She also administered the
abbey of San Pedro de Siresa. In 1080, she witnessed the will of Count
Sancho Galíndez. ==Policy==