This fresco depicts the miracle of the Host, which took place in the church of St. Christina in the central Italian town of Bolsena in 1263. While on a pilgrimage to Rome, a Bohemian priest experienced doubts about the doctrine of transubstantiation as he celebrated Mass, but was converted when blood miraculously began to drip from the Host. The miracle of the Mass of Bolsena led Pope Urban IV to institute the feast of Corpus Christi in 1264. In spite of the intrusive doorway, Raphael created a unified scene by raising the altar area, which has a columned architectural backdrop, and relegating the congregation and the pope's kneeling retinue to the foot of the altar podium. The two levels are linked by glances and gestures, which provide a commentary on the action. The figures also serve as examples to the viewers, calling upon them to be equally moved. In addition to Julius II, other figures have been identified as portraits of contemporary individuals. The male figures right of foreground are of particular interest, as they constitute one of the earliest depictions of the Swiss Guard, which was established by Julius II in 1506.