The two bronze papal tombs (Sixtus IV and Innocent VIII) executed between 1484 and 1496 by the Pollaiuolo workshop for St Peter's, Rome, were the grandest of the 15th century, and the only tombs to be transferred into the new basilica when Old St Peter's was demolished in 1506. Around the recumbent effigy of Pope Sixtus IV, whose face was evidently modeled on a death mask, reliefs of seven Virtues decorate the top of the tomb. This rests on a base with steeply sloping sides, which are decorated with personifications of the Liberal Arts in high relief separated by rich acanthus decoration. The iconography was unprecedented: the Liberal Arts had never before been included on an ecclesiastic's tomb, although they were appropriate for Sixtus' wide-ranging intellectual interests.