Both in Greek and Roman ancient times and Judaism, ‘prophetic’ dreams used to have an important political function. A great role was still ascribed to them in the Christian Middle Ages, what can be seen best in the example of the iconography of two ‘founder’s legends’: one of Santa Maria Maggiore basilica in Rome (Filippo Rusuti’s mosaics on the facade, 1295) and the other one of the Franciscan...