St. Catherine's Monastery, Mt. Sinai
This is the earliest known image of the Transfiguration. Light rays emanate from Jesus to the five figures, who are labeled (left to right) Elijah, John, Peter, James, Moses. To communicate the otherness of the event the artist avoids making the scene look like a space. The mountain is not represented, and Peter's knees lap out of the frame.
More of the Transfiguration
Source: Wikimedia Commons