The Titulus of Palermo Cathedral was the space located at the end of the nave and before the main apse, where the Canons Regular took their seats in the choir and which contained both the bishop’s chair and the royal seat. The sacristies of the Canons and Benefactors were located on the southern front of the Titulus and the Antititulus, which have now been changed into the Cathedral Treasury rooms. The Antititulus is a longitudinal room, with an almost transept-like appearance, arranged in front of the three apses and separating them from the Titulus. The entirety of this spatial system represented the ‘Great Presbytery’, which can still be found in its original form in Monreale Cathedral.