This altarpiece, with its triple dedication to Saint Peter, the Virgin Mary, and Saint Blaise, very likely served as the retablo mayor, or high altarpiece, of a now unknown church. The paintings are stylistically consistent with a signed altarpiece by Martín de Soria dated to 1485 in the parish church of Pallaruelo de Monegros (Huesca). Most medieval altarpieces like this one were dismantled and sold off as individual paintings. Although now in a modern frame and configuration, this altarpiece is thought to be intact, and is therefore quite rare.

The overall stepped, roughly triangular shape of this altarpiece is characteristic of large-scale Aragonese retablos. This format sought to take full advantage of the height and curve that signaled the most sacred of medieval spaces. Architecture and painting, therefore, worked in tandem to shape religious experience. Other practical features include the formula of votive figures enthroned in tall, narrow panels and flanked by scenes illustrating key events in their lives, or hagiographies, such as miracles performed and martyrdom endured. The bottom row of the altarpiece—the predella or banco—depicts the twelve apostles but now lacks its central element, which probably was either a panel of the Man of Sorrows or a small cupboard for the reserve sacrament called a tabernacle. The narrow vertical rows with angels and standing saints on the retablo’s outer edge are all that survive of the lost canted frame or guardapolvos (“dust guard”), another practical but nevertheless meaningful element of this piece of sacred furniture.