The complex, covering some 20,000 square metres, is one of the largest constructions of its kind in Spain and is currently home to the Seminario Mayor and a hotel. It also houses a museum with a permanent collection, including the church with altarpieces and choir stalls.
The church and the monastery were built over the course of more than a century. Construction started in on the church in 1590 and concluded in 1747 with the completion of one of the interior cloisters. The origin of the community is not known, but it is supposed to be linked to the appearance of the remains of the Apostle. What is known, however, is that there was a primitive Romanesque building on the same site, of which hardly any traces remain. The few architectural elements that survived were used for the foundations of the current building, as can be seen in some of the exterior walls.
The Church of San Martiño Pinario combines features from the Renaissance and Baroque periods, very common throughout the city. The floor plan consists of a single nave, with side chapels forming a rectangle. The huge central nave is covered with a cannon vault with false ceilings, and the three side chapels have vaulted ceilings. The large ribbed dome, supported by pendentives, gives the construction a light, airy feeling. Notable interior features include the chapels, mostly built in the 18th century, and the three altarpieces from the same period. There is also a splendid lower choir dating from the 17th century, depicting scenes from the life of the Virgin. The three altarpieces were designed by Fernando de Casas. Over the years, the monks also commissioned and added images, most of which were made by the sculptor José Ferreiro. On the outside, the church facade, which is accessed via an incredibly beautiful Baroque staircase, is divided into three vertical bodies, corresponding to the interior divisions of the temple, the only richly decorated portions of the outer walls.The facade is covered by a number of carvings of saints, and is crowned by the scene of San Martiño.
The Monastery itself consists of two cloisters: the Offices and the Gatekeeper's House, built in the 18th century. On the outside, a notable feature is the main facade, designed by Fray Gabriel de las Casas, on which construction was started in about 1697. It consists of three parts: the front and two square-shaped side towers. The main door is framed by four large Doric columns and above it there is a niche bearing the image of San Benedictino. On the entablature there are four pinnacles and the crest with a royal coat of arms and a crown. Completing the composition is a group of sculptures of San Martiño sharing his cape with a poor man.