Santa María de Santa Cruz de la Serós is a former Benedictine nunnery. It is located about ten miles from Jaca, in the village of Santa Cruz de la Serós, which is named after the nunnery. The church of San Caprasio, built between 1020 and 1030, a half century earlier than Santa María, stands nearby in the same village.
In the 11th century it functioned as a "family monastery" for the royal family of Aragon, that is, female members of the family ruled the monastery from within while family members outside the monastery patronised it.
The date of Santa María's foundation is unknown. It is first mentioned in a document of 1070. In that document, Sancha de Aibar, mother of King Ramiro I, grants some land to Ramiro I's daughter Sancha on the condition that she leave them to the nuns of Santa María on her death. Although there is no earlier reference to the nunnery, it appears to have been in existence for some times, since it had both an abbess, Menosa, and a church building at the time of Sancha's grant, since the document itself was drawn up "in the atrium of Santa María, before the abbess Lady Menosa". In her will of 1095, the younger Sancha specifies that her bequest should go to "the workshop of the church for Santa María". Besides Sancha, Ramiro I's other two daughters, Teresa, his eldest who never married, and Urraca, who may have been married to Count William Bertrand of Provence, both made donations to Santa María before entering it as nuns. In a document dated 15 March 1061, Ramiro I commends his daughter Urraca to the abbess and nuns of Santa María, but this document is probably a forgery. Urraca seems to have entered the nunnery towards 1070.
Ramiro I's daughter-in-law, Felicia, wife of King Sancho Ramírez, donated an evangelary to the nunnery. It is now lost, but either of two surviving silver-gilt plaques incorporating some Byzantine ivories is thought to have been its book cover. The covers, one of which bears Felicia's name, now reside in the Metropolitan Museum of Art in New York. Both may have at one time belonged to Santa María.