The Triptych is painted on both sides by Giotto around 1320. This painting was once on the altar of Saint Peter's Basilica. In the middle panel on the front, you can see St. Peter sitting in a chair: to the left of his feet you can see the cardinal who commissioned the work, holding up a model of the triptych itself. Make sure to look at the back as well, where you'll see the scenes of the Martyrdom of Saints Peter and Paul, one crucified upside down and the other decapitated.
