The wall paintings of the Sistine Chapel are among the most important examples of the type of painting developed in Florence in the later fifteenth century.
The five artists brought to Rome to execute them came from various different art centres: Botticelli, Ghirlandaio and Rosselli from Florence, Perugino from Umbria, Signorelli from Cortona.
Perugino's contribution was the largest, with the altar wall paintings and three additional pictures.
Recent scholars have concluded that it was he who was in charge of the whole project and who produced the overall design.
It is true that in "the Christ Handing the Keys to St Peter" his portraits appears next to those of the architect and builder.