Lippo Memmi
The date of the painting is specified in a fragment of the original frame, now embedded in the 19th-century renovation. It lists the name of Simone Martini and his brother-in-law Lippo Memmi (), although it is unknown which parts they executed. A hypothesis is that Martini painted the central panel, while Memmi was responsible for the side saints and the tondoes with prophets in the upper part.