Most extraordinary of all is the interior of the dome, entirely covered with mosaic showing the Angelic Hierarchies, Scenes from Genesis, Scenes from the life of Joseph the Patriarch, Scenes from the life of Christ, Scenes from the life of St. John the Baptist, and the Last Judgement. The mosaics in the apse are by the Franciscan Jacopo di Torrita (1255). Covering the inside of the Baptistery with mosaic was a difficult and costly undertaking. Work possibly began around 1270 and continued until the beginning of the following century; according to some authorities, Venetian craftsmen were employed, certainly assisted by important local artists who supplied the cartoons, such as Coppo di Marcovaldo (who was responsible for Hell), Meliore, the ‘Magdalene Master’, and Cimabue (to whom the earlier Scenes from the life of the Baptist are attributed).