The Palacio de Gelmírez is named after the city's first archbishop who was responsible for the construction of the cathedral in the late 1120s. Nowadays it is part of the city's cathedral museum. Its highlights are the medieval kitchen and the remarkable synod hall (where members of the ecclesiastical order would meet). Thirty metres in length, this 13C room crowned with ribbed vaulting has just a single central arch, known as the Arco del Palacio.