The Dome of the Mausoleum of Galla Placidia

5th century
Mosaic
Ravenna, Italy

Christ and the evangelists are represented by the cross and the four winged creatures.

This image in full resolution

Detail: the eagle
Detail: the angel
Detail: the ox
Detail: the lion

More of the Cross
More of the Evangelists

Photographed at the site by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.