Fortaleza de Sarria, Medieval castle in Sarria, Spain.

The Fortaleza de Sarria is a medieval fortification in Sarria, Galicia, of which only one flank tower, the Torre del Batallón, remains. Built of granite ashlars with a rounded plan, it keeps its merlons and reaches 14 to 15 metres high. Its interior is covered at about seven metres by a slightly pointed vault.

The fortress probably dates from the 12th century, under Gutierre Ruiz de Castro and Elvira Osorio, lords of Lemos and Sarria, though documents give no exact date; it stood on a height over the Vila Nova de Sarria, likely on an earlier castro. From 1325 to 1430 it was tied to the life-long title of count of Trastámara, Lemos and Sarria, held by Álvar Núñez de Osorio, the infante Enrique de Trastámara, Fernán Ruiz de Castro and Bertrand Duguesclin. The Irmandiña Revolt destroyed it in 1467-1469, and Pedro Álvarez Osorio, first hereditary Count of Lemos, had vassals of the Cinco Pobras rebuild it, hauling stone with ox-carts. The Catholic Monarchs protected it and granted it to the counts of Lemos; on 1 May 1543 Charles V made Fernando Ruiz de Castro y Portugal marquis of Sarria.

The tower keeps coats of arms of the Castro, Enríquez and Osorio families, carved in stone on the surviving flank tower. They record the noble houses that held Sarria, and the tower is still known locally as Torre del Batallón after the Pérez-Batallón family that owns it.

The tower and its plot are private property of the Pérez-Batallón family; the enclosure is fenced and visits are not allowed, so it can only be seen from outside. Sarria council has long sought to buy it so it can pass into municipal heritage. It is on the Red List of Hispania Nostra because of its abandoned state.

The tower is listed on Hispania Nostra's Red List of Heritage in Danger because of its abandoned state, and the Sarria council has for years been negotiating to buy it from the Pérez-Batallón family so it can pass into municipal ownership.