The Chapel of the Holy Sacrament and of the Holy Christ of Lepanto was constructed by Arnau Bargués in 1407.

It was the Chapterhouse of the Cathedral until 1676, when Saint Olegarius was canonized and the room became his mausoleum.

The Chapel of the Holy Sacrament has a rectangular floor plan, covered by a great star vault. The central keystone of the chapel represents the Pentecost and was created by the sculptor Joan Claperós in 1454.

Inside the chapel is the Baroque sepulcher of Saint Olegarius - bishop of Barcelona – and, above that, the Holy Christ of Lepanto dating from the 16th century.