For many decades, the traditional attribution of the frescoes of the "Vita di San Francesco" in the Upper Basilica has been questioned, particularly by English art historians like Rintelen, Oertel, or Meiss. Italian scholars, however, remain mostly convinced by Vasari's attribution of the frescoes to Giotto. The recent conservation by after the 1997 Umbria and Marche earthquake shed new light on the debate. Zanardi supported the opinion of Federico Zeri that thought the frescoes executed by a painting of the Roman school, perhaps Pietro Cavallini, the only great Gothic painter not confirmed to have contributed to the basilica, or his contemporaries Filippo Rusuti and Jacopo Torriti.