Vision of St. John on Patmos

The Vision of St. John the Evangelist at Patmos (1520-1522) is a series of frescoes by the Italian late Renaissance artist Antonio Allegri da Correggio. It occupies the interior of the dome, and the relative pendentives, of the Benedictine church of San Giovanni Evangelista of Parma, Italy.
The centre of the cupola is occupied by an illusionistic space based on series of concentric planes indicated by the clouds, from which the apostles stretch out. Starting from the border of the dome, the clouds thin out and open to a shiny light Christ descending towards the floor of the nave. The scene is a faithful rendering of John's Book of Revelation (I,7). The figure of St. John leans from the drum of the dome. This part of the fresco was hidden to the people present in the church, but visible to the monks in the choir and under the dome.
In the four pendentives Correggio painted, coupled, the Four Evangelists and the Four Doctors of the Church. These are: 
and, respectively,