The drum of the dome has eight frescoes by Sacchi. These frescoes are separated by ribbed Corinthian pilasters folded into the corners, which support the entablature of the cupola. This is decorated in blue and gold, and is separated into eight sectors by wide ribs. Each sector has a round window in a lunette, then more bees with a Sun in Splendour symbol. The sectors meet at a large oculus containing the Dove of the Holy Spirit in glory