The cold room or frigidarium was the first room within the baths as such. Access was through two double doors that closed by the force of gravity and practically sealed the room, helping to keep a low temperature.
Following Roman and Arab tradition, bathers would immerse themselves in the frigidarium at the end of their visit.
Here, they would bathe in cold water. No specific cooling process was required; rainwater stored in a cistern was used. The paving around the pool was slightly raised on two sides to protect users from contact with damp surfaces. This is the smallest room; the ceiling is a lowered groin vault supported in part on two arches with a middle column on the crosswise sides.