The medieval building of the monastery of Santa Maria de Alcobaça is located in the central part of Alcobaça. The city received its name in honor of the rivers Alcoa and bass, at the confluence of where it is located.

The monastery was founded by the first king of Portugal, Afonso Henriques, in 1153. The church and monastery were the first buildings in Portugal, built in the Gothic style, and are considered the most important historical monuments of the Middle Ages. In 1989, UNESCO made the monastery of Santa Maria de Alcobaça in the World Heritage List.

The monastery was one of the first churches of the Cistercian monastic order in Portugal and was built by the King of Portugal Afonso Henriques in honor of his victory over the Moors. Construction of the monastery was part of the strategy of the king, who wanted to strengthen its authority in the newly established empire and to promote the colonization of land recently conquered from the Moors.

At the time of the construction of the monastery in 1178, the monks of the Cistercian Order were in the city for over 25 years. All the while, they lived in wooden houses and moved to the monastery in 1223. The church was finished much later and is considered the largest church in Portugal. The final touch to this ensemble - covered gallery Silencio (Silence of the Gallery) in the Gothic style, which was built in the XIII century.

Library Alcobaça is considered one of the largest libraries of the Middle Ages in Portugal. In 1810, during the French invasion, many books were stolen. The rest of the books now kept in the National Library of Lisbon.

During the reign of King Manuel I, I was completed on the second floor covered gallery Silencio and built the sacristy Manueline style. The monastery was further expanded in the XVIII century construction of a new cloister and tower of the church was renewed in the spirit of the Baroque facade. Inside the church are the tombs of Dom Pedro I and Dona Inês de Castro, made in the Gothic style, and is an excellent example of art of the XIV century of Portugal.