The west end of the transept and the apse have been decorated with many frescoes by Cimabue and his workshop (starting in c. 1280). The magnificent "Crucifixion", with Saint Francis on his knees at the foot of the Cross, stresses again the veneration of the Passion of Christ by Saint Francis. The frescoes of Cimabue soon suffered from damp and decay. Due to the use of lead oxide in his colours and to the fact that the colours were applied when the plaster was no longer fresh, they have deteriorated and have been reduced to photographic negatives.