The ruins of the Domus da Escola Velha da Sé represent important moments in the evolution of the urban fabric of Braga. It is a set of structures that correspond to a private building built in the 1st century AD, and whose occupation lasted until the 5th century AD. Also visible here are the remains of the foundations of the medieval wall, which are attached to a panel of one of the towers that once formed part of this defensive structure of Braga.

It is also possible to see a permanent exhibition at this site, which aims to show techniques and tools associated with the execution of mosaics from the Roman era, whose vestiges have also been exhumed at this archaeological site.