Chap. VII. PIETRO PERUGINO. 183 them. They may be likenesses of Perugino’s associates in Rome at the period of his stay, or of men who desired to see their persons immortalized in a sacred place. But we do not see amongst them either Pinturicchio or della Gatta, whose labours are indeed more easily traced in the Moses and Zipporah, and in the Baptism, than they are in the Delivery of the keys. 1 As a wall-painter, Perugino at the Sixtine followed the practise familiar to him in the production of temperas on panel. He laid in the flesh with the usual pale grey- green, and stippled the lights and shadows over all, re touching the dry surface at last with rough hatchings which have been blackened by the effects of time. His system was that which Pinturicchio continued at Rome after Perugino’s departure. This event, no doubt, occurred after the completion of the Sixtine chapel in 1486; and this we infer not from any knowledge as to the manner in which Perugino’s masterpieces were received, but because he had returned to Florence in the autumn of that year. It appears from the criminal records of Florence that Perugino and a companion called Aulista di Angelo of Perugia were con victed of having disguised themselves on some of the long nights of December, and waited with staves at the corner of a street to waylay some person near S. Pietro Maggiore. The evidence adduced before the “otto di cuslodia” in their sittings of July 1487 established most damning facts against Aulista, who was proved to have murdered one man, and struck or wounded others at Rome. It further appeared that he had proposed to mur der the person against whom he and Perugino had a grudge, but that the latter wished to end the matter with a drubbing only. Fortunately for the threatened party, the conspirators were taken into custody, and sentenced, 1 Vasari mentions the Sixtine frescos (VI. 40—41).