He was then summoned to Pisa in order to finish, below the stories of S. Ranieri in the Campo Santo, certain stories that were lacking in a space that had remained not painted; and in order to connect them together with those that had been made by Giotto, Simone Sanese, and Antonio Viniziano, he made in that place, in fresco, six stories of S. Petito and S. Epiro. In the first is S. Epiro, as a youth, being presented by his mother to the Emperor Diocletian, and being made General of the armies that were to march against the Christians; and also Christ appearing to him as he is riding, showing him a white Cross and commanding the Saint not to persecute Him. In another story there is seen the Angel of the Lord giving to that Saint, who is riding, the banner of the Faith with the white Cross on a field of red, which has been ever since the ensign of the Pisans, by reason of S. Epiro having prayed to God that He should give him a standard to bear against His enemies. Beside this story there is seen another, wherein, a fierce battle being contested between the Saint and the pagans, many angels in armour are combating to the end that he may be victorious. Here Spinello wrought many things worthy of consideration for those times, when the art had as yet neither strength nor any good method of expressing vividly with colour the conceptions of the mind; and such, among the many other things that are there, were two soldiers, who, having gripped each other by the beard with one hand, are seeking with their naked swords, which they have in the other hand, to rob each other of life, showing in their faces and in all the movements of their members the desire that each has to come out victorious, and how fearless and fiery of soul they are, and how courageous beyond all belief. And so, too, among those who are combating on horseback, that knight is very well painted who is pinning to the ground with his lance the head of his enemy, whom he has hurled backwards from his horse, all dismayed. Another story shows the same Saint when he is presented to the Emperor Diocletian, who examines him with regard to the Faith, and afterwards causes him to be put to the torture, and to be placed in a furnace, wherein he remains unscathed, while the ministers of torture, who are showing great readiness there on every side, are burnt in his stead. And in short, all the other actions of that Saint are there, up to his beheading, after which his soul is borne to Heaven; and, for the last, we see the bones and relics of S. Petito being borne from Alexandria to Pisa. This whole work, both in colouring and in invention, is the most beautiful, the most finished, and the best executed that Spinello made, a circumstance which can be recognized from this, that it is so well preserved as to make everyone who sees it to-day marvel at its freshness.