|The Four Evangelists
Since at least the 4th century images of Christ in triumph often surround him with the symbols of the four evangelists: for Matthew, a young man or angel; for Mark, a lion; for John, an eagle; for Luke, an ox -- all of them with wings, as at left. This is based on Revelation 4:2, 6-8 (cached), which in turn follows Ezekiel 1:5-10 (cached) and 10:14 (cached).
It is also common to add images of the evangelists as actual men -- as at left, where they sit writing at their desks.
The use of the four creatures, with or without corresponding human figures, will also be seen in a great variety of other compositions, usually in connection with some image of Christ.
At left, a tympanum at León Cathedral
4th century mosaic
5th century mosaic
6th century mosaic