It is especially notable for its fresco paintings by Fra Angelico (1447–1451) and his assistants, who may have executed much of the actual work.

The chapel is located in the Tower of Innocent III, in the most ancient part of the Apostolic Palace.

The scenes of St. Stephen follow the Biblical account in the Acts of the Apostles, while those of St. Laurence are patterned after the older cycles in the basilica of San Lorenzo fuori le Mura, where he is buried.

The frescoes underline the similarities in the lives of the two figures: both were ordained deacons, both gave alms to the poor and both were martyred after a courageous declaration of faith.

The frescoes, full of fine architectural details, allude also to Nicholas V's desire to rebuild Rome as the new capital city of Christianity.