This is a monastic foundation of a familial nature with a dual character, meaning it housed both male and female communities. Santa María de Mezonzo was founded around the year 930 by Reterico, its first abbot, and was donated in 970 to King Alfonso III the Great (c. 848–910). Pedro de Mezonzo (c. 930–1003) joined this house as a monk, where he received his formation.
In 955, this house was united with Monastery of Sobrado dos Monxes, and Pedro de Mezonzo was elected abbot of that establishment. In 985, he also became bishop of Iria, the predecessor of the diocese of Santiago. The Church venerates him as a saint. Despite being dependent on Sobrado, when that monastery was abandoned in the second half of the 11th century, the house of Mezonzo continued its activity, likely as a Benedictine monastery. In 1157, it was mentioned as a priory of Sobrado, which by then had been restored and affiliated with the Cistercian order. In 1183, Mezonzo belonged to Ferdinand II of León and Galicia, who ceded it to the bishopric of Santiago. By the late 14th century, an abbot of Mezonzo is mentioned, suggesting that the monastery had regained its independence.
However, by the late 15th century, the monastery was in deep decline: the abbot was accused of leading a dissolute life, which prompted a reform led by the monastery of San Martiño Pinario, which ultimately took control of Mezonzo. Once the situation was resolved, that abbot, along with the abbot of Santo Antolín de Toques, who was in a similar position, was authorized to reside in Mezonzo for the rest of his life. The site remained a property of San Martiño, holding the title of priory and serving parish functions.
The church, which is preserved, features a basilica floor plan with three naves and three apses, without a transept. Its construction took place in various stages, between the Romanesque and Gothic periods, from the late 12th century to the early 13th century. It has three simple Romanesque-style doorways, located on the west, north, and south sides of the building.
Western portal
Western portal
South portal
South portal
North portal
- FRANCO TABOADA, José Antonio (2009). Igrexas dos mosteiros e conventos de Galicia. Xunta de Galicia
- FREIRE CAMANIEL, José (1998). El monacato gallego en la alta edad media, vol. II. La Corunya: Fund. Pedro Barrié de la Maza
- PÉREZ DE URBEL, Justo (1998). San Rosendo y Celanova en el Cartulario de Sobrado. Signo, núm. 5
- PÉREZ GONZÁLEZ, José María; dir. (2013). Enciclopedia del románico en Galicia. A Coruña. Aguilar de Campoo: Fundación Santa María la Real
- PÉREZ RODRÍGUEZ, Francisco Javier (2008). Mosteiros de Galicia na Idade Media. Ourense: Deputación Provincial de Ourense
- YEPES, Antonio de (reed. 1960). Crónica General de la Orden de San Benito. Vol. II. Madrid: Atlas
- ZARAGOZA PASCUAL, Ernesto (1993). La reforma monástica del monasterio de Santa María de Mezonzo (1498-1499). Compostellanum, vol. 38
The church is located in a secluded area between A Coruña, Santiago de Compostela, and Lugo.