If you look at the ceiling of the dome you will see eight paintings. The larger pictures show the four evangelists: Matthew with an angel, Mark with a lion, Luke with a bull and John with an eagle. Between the four evangelists there are four smaller paintings that figuratively represent the four Christian virtues of faith, love, hope and charity. Faith is represented with a cross and a chalice, charity is represented giving money to an outstretched hand, love is represented by a mother with her children, and hope is represented with a ray of light from God. These representations of the virtues are further enhanced by the colors that fill the entire main space of the church.
The original painting was done by the Venetian painter Giovanni Battista Grone. The ceiling paintings that you can see today were painted by Christoph Wetzel, who was commissioned to restore Grone's paintings in their original style.