Castropol was one of the last stages on the Way of St James in Asturias, to the point that one of the side doors of this church is called the "French door".
It has three naves, the centre one being wider and higher, separated by columns and covered by stellar vaulting. The tower, added in the 19th century, is located at the west end. Overlooking the town, this high, quadrangular tower has a slate roof crowned by a spire. The ground floor forms an open porch that houses the portal.
The church preserves a good set of Baroque altarpieces: at the west end of the left nave, there is one dating from the early 18th century, divided into three panels separated by Solomonic columns, while the gilded, polychrome altarpiece in the Chapel of the Marchioness, dating from the 18th century, was commissioned by the Marquises of Santa Cruz and is dedicated to the Assumption of the Virgin. The Montenegro Family Chapel, dating from the 17th century, houses the family pantheon, with its noble coats of arms.
