The Chapter Room was originally the sacristy. Like the high choir (on the upper floor), this room was started by Diogo de Arruda (here he worked between 1510-1513) and finished by João de Castilho (here he worked between 1514-1553), creating the connection to Charola, through of an elevated level door with the nave of the church, and ending the vault of the nave of the church as well as its entrance portal in 1515.