The painting that has sparked the interest of academics is the large decoration of the gable on the back wall. It clearly shows a group of knights attacking a fortress. A large portion of the fresco is no longer visible, but the traces allow the viewer to reconstruct the scene. The anonymous painter chose to paint the actual bricks of the wall with a reddish colour which transforms them into a besieged castle. The work, which can be seen in relation to the ships on the wall of the entrance because of its style, is made more interesting by the different banners carried by the knights, which indicate the presence of a great many troops commanded by the various noble families of the area. One banner in particular stands out, it depicts a white cross on a red background.