The iconography of the ceiling is interesting - reminiscent of Freemasonry symbolism. The ceiling is panelled with 36 squares. 24 squares have a quatrefoil decoration containing alternate decorations of an olive branch (symbolic of peace) and a crown over a thornless rose (symbolic of the Virgin as Queen of Heaven). Twelve squares over the altar are symbolic of Christ's crucifiction, showing: a crown of thorns, a robe, 3 nails and crossed swords, a ladder, pincers and hammer, the sun and moon, pillar and flail, dagger and lantern, and various monograms. The monogram of PAX means peace and IHS and INRI refer to Jesus of Nazareth. The 12 squares also refers to the number of apostles.