Focus on Testament and Death of Moses and discuss the History.
On 27 October 1480 a group of Florentine painters left for Rome, where he had been called as part of the reconciliation project between Lorenzo de' Medici, the de facto ruler of Florence, and Pope Sixtus IV. The Florentines started to work in the Sistine Chapel as early as the Spring of 1481, along with Pietro Perugino, who was already there. Neither Bartolomeo della Gatta nor Luca Signorelli (who was thirty at the time) appear in the official contracts signed between the Papal court and the painters, but they were most likely among the assistants of Perugino, who was the general superintendent of the works. Signorelli is mentioned in the Sistine Chapel after his master left in 1482, as the author of the Disputation over Moses' Body on the entrance wall (repainted by Matteo da Lecce in 1574 due to its poor state).It has been supposed that Perugino provided at least the layout of the fresco, while its realization, basing on a comment by Giorgio Vasari, had been assigned traditionally to Signorelli. Studies by art historians such as Mario Salmi, reduced Signorelli's presence in the work, and attributed most of the painting to Bartolomeo della Gatta, a painter influenced by the purity of Piero della Francesca and the early Perugino.
The theme of the decoration was a parallel between the Stories of Moses and those of Christ, as a sign of continuity between the Old and the New Testament. A continuity also between the divine law of the Tables and the message of Jesus, who, in turn, chose Peter (the first alleged bishop of Rome) as his successor: this would finally result in  a legitimation of the latter's successors, the popes of Rome.
Sistine Chapel Giorgio Vasari Florence Old Jesus Moses Piero della Francesca Rome Bartolomeo della Gatta Pope Sixtus IV left Matteo da Lecce Pietro Perugino New Testament Lorenzo de' Medici Mario Salmi Luca Signorelli