The left wing of the triptych is depicted by von Werl, who is praying with St. John the Baptist. . Heinrich von Werl was a Franciscan theologian.
The artist painted it in a long light room with a wooden screen, on which hangs a metal mirror with a room reflected in it. Behind the canon stands his spiritual patron John the Baptist, dressed in a scarlet robe and holding a lamb in his arms. This iconographic attribute of the Holy. Behind the figure of John the Baptist is a window, in it you can see the landscape painted with precision by the miniaturist.