Over the altar is a Byzantine icon of the Madonna and Child, known as the Madonna d'Aracoeli, and is considered by modern scholars to be an 11th- or 12th-century copy of the so-called Madonna of S. Sisto. In the Middle Ages it was believed to have been painted by the Evangelist Luke and to have performed numerous miracles. The two angels holding up the garlands suspended above the icon and supporting large shields emblazoned with the initials SPQR indicates the icon as the protector of Rome.