The chapel is famous for its fresco cycle painted around 1246, the year it was consecrated as the private chapel of the Cardinal's Palace. This cycle is political propaganda (in the secular sense), and depicts the unhistorical legend of Pope Sylvester I and Emperor Constantine I, including the fictional baptism of the emperor by the pope and (importantly) a depiction of the Donation of Constantine which was based on a forged mediaeval document. The work was painted in the context of the confrontation between Pope Innocent IV and the newly excommunicated Holy Roman emperor Frederick II, and was intended to illustrate the alleged sovereignty of the Church (Pope Sylvester) over the Empire (Constantine).