In the northern apse of the Cathedral is the Chapel of the Blessed Sacrament, entirely decorated with gilded stucco. The centrepiece of the chapel is the altar made entirely of lapis lazuli, an expression of the Baroque era, dated 1653 and designed by the architect and sculptor Cosimo Fonsaga (Fanzago). It was commissioned, according to sources, by Archbishop de Leon, for a sum of 15,000 scudi. After the prelate’s death in 1656, it was completed by the Senate of Palermo. The altar houses the Blessed Sacrament.