The Archaeological Museum of the Martins Sarmento Society is one of the oldest archaeological museums in Portugal. It began to be built in 1885, from a central core formed by the property that belonged to Martins Sarmento, and is distributed in the premises of the extinct Convent of Santo Domingo (modern staircase and Gothic cloister). Maintaining essentially the original exhibition structure, the Museum is also, today, a unique memory of the museological concepts of the time in which it was created.
The collections are distributed in two areas. The section of Prehistoric and Protohistoric industries, in the upper gallery of the aforementioned cloister, whose collection is distinguished by the variety, quantity and quality of the pieces on display, with emphasis on the collections of prehistoric artifacts from Penha and the proto-historic materials from Citânia de Briteiros and Castro de Sabroso. Also noteworthy is the votive cart from Vilela, one of the icons of the Iron Age.
The Epigraphy and Ancient Sculpture section is distributed along the staircase of S. Domingos, the ground floor and the garden. It is made up of around two hundred pieces that include sculptures, honorific inscriptions, monuments, sepulchral pieces, votive signs, anepigraphic signs, milestones, shields, elements of architectural structures, pieces of ornamental art, emblems and objects for industrial use. Two sculptures of Galician-Portuguese warriors, from Fafe and Felgueiras, stand out.