The back wall shows, over the squares in fake marble, a fragmentary representation of the Last Judgement. The writing indicating the author is particularly useful: “Grixopulus pictor parmensis depinxi hoc opus”. Although the word “parmensis” is partly erased, the writing clearly refers to a master, perhaps of eastern origins, working in Mantua in the fifties of the thirteenth century. This is confirmed by a document dating to 1252 that links the artist to the bishop Martino, also from Parma. Some experts claim the painter is also the author of the upper frescos of the baptistery of Parma, and of other works in Piedmont and in Savoia. He is the author of the religious frescos in the Palazzo della Ragione, which have many elements in common with the square shaped decoration in the bottom section of the wall.