The Sacristy, from 1622, is a work that is stylistically located in the transition from Mannerism to Baroque, its design is by Pedro Tinoco, a Lisbon architect.
The sacristy is adorned by a magnificent vault and 17th century tiles that imitate Persian tapestry. This space can be considered a small museum, given the valuable works found in it, such as PENTECOSTES, by Grão Vasco; ECCE HOMO and CALVÁRIO, by Cristovão de Figueiredo and the large canvas of DESCIMENTO DA CRUZ, by André Gonçalves.
Other important objects are also part of the rich collection, such as the valuable Mirror with a frame from the 18th century and the huge wooden images next to the Cross: Our Lady and St. John the Evangelist, and on the opposite side, that of Santa Gúdula and St. Gertrude, all from the 18th century.
There is also a chest of drawers with ivory inlays that go along the length of the entire Sacristy. This chest of drawers was created by Samuel Tibau in the 17th century.
Next to the door that gives access to the Chapter Room, there is the Amictuário, which is a type of closet that contains, in each of the lockers, some ivory plates and the identification of the last friars that used them.