The windows in the apse honor the five founders of religious orders, Saint Romuald (+1027), founder of the Camaldolese; Saint Bernard (+1153), famous Cistercian abbot; Saint Benedict (+547), founder of the Benedictines; Saint Dominic (+1221), founder of the Dominicans; and Saint Francis (+1226), founder of the Franciscans.

The top of the picture shows the nine Choirs of Angels and below, in the middle of the picture, is Lamb of God.