The series of Pontiffs ran along all the walls of the Chapel starting from that of the altar, in the centre of which could be seen Christ and the first pope Peter, as well as Linus and Cletus. The four figures were lost when Michelangelo, by order of Paul III, painted the Last Judgement on this wall in 1536. The Pontiffs are arranged in couples in niches beside the windows. The series does not run along the one wall, but they alternate with the opposite wall. The authors of the series are the same as those of the cycles of the lives of Moses and of Christ, that is to say, Pietro Perugino, Sandro Botticelli, Cosimo Rosselli and Domenico Ghirlandaio. The position of the various personages differs only slightly. They are usually shown as a full figure, in three-quarter profile with a book or scroll, or in the act of conferring blessing.