However the authorship of Giotto is disputed, due to the ambiguous attributions given in early descriptions of this work. Many Italian critics continue to support the authorship of Giotto and his workshop. But because of small differences in style with the frescoes of Isaac, it is thought that several or even all of these frescoes were painted by at least three separate painters, using the original concept of Giotto : the Master of Legend of Saint Francis (the principal painter and probable supervisor of the cycle), the Master of the Obsequies of Saint Francis and the Cecilia Master.