Here I must leave the consideration of the authorship of these frescoes; as I said in the beginning, it is a much vexed question, and one that there is at present no positive evidence for deciding; the one thing that is certain is that in a very short time, if it has not happened already, the frescoes will, to all intents and purposes, have entirely vanished.
Crowe and Cavalcaselle hold that there were a series of painters who worked at the Upper Church, and that the whole history of the revival of early Italian art is comprised and explained in these paintings, and seem to hold that Giotto painted only one or two of these frescoes; while, lastly, in one of Dr. Dohme's German series of biographies, which is the latest work issued on this subject, we have the author maintaining the thesis that Giotto painted all these frescoes (in the lower row), and that when he had finished this series he began again upon those of the Lower Church.
Of the various opinions, those of Vasari and Lindsay can, I think, be shown to be wrong from a comparison of the dates of Giotto's works. In the first place there is no evidence whatever to hint at two visits to Assisi, except Vasari's statement that Giotto was invited to Assisi by Fra Mure. Now Fra Mure, who was general of the Franciscan order, only held that post between 1296 and 1302, and therefore if he invited Giotto to complete the frescoes of the Upper Church, it must have been between those years; but from a register preserved in the Vatican, the famous _Navicella_ mosaic was executed by Giotto in 1298, and that he was still at Rome in 1300, is proved by a portion of a fresco representing Pope Boniface announcing the opening of the Jubilee, which took place 1300, and upon the completion of which work Giotto betook himself to Florence, and painted the famous frescoes in the Bargello, in one of which the portrait of Dante occurs. Dante was exiled in 1302, and this, and many minor considerations, point to the date 1301-2 for the execution of these frescoes. It is therefore easy to see that Giotto could not have had the possibility of accepting Fra Mure's invitation between the dates of 1296 and 1302. The question remains whether the lower row of frescoes were executed by Giotto at any subsequent period?