The Monastery of Paço de Sousa was founded in the 10th century. The current church was built in the 13th century in the Gothic style, the chancel, the sacristy, the cloister and what remains of the monastic building date from the 17th and 18th centuries. The ensemble was the target of interventions in the 19th (1883 and 1887) and 20th (1937-1939) centuries.

Inside the church is one of the most beautiful pieces of national Romanesque sculpture: the tomb ark of Egas Moniz de Ribadouro, the legendary aide of D. Afonso Henriques, the first king of Portugal.

It presents an architectural style in the transition between Romanesque and Gothic styles. The monastery comprises a Romanesque church of three naves of considerable proportions, in which a beautiful rose window stands out. Its layout influenced the entire Penafiel region, and it can be said that this temple fits in the style of other Romanesque monuments, such as those of Roriz, Gândara, Travanca and Pombeiro.