Introduction: Symbolic Thinking
The appreciation of nature involves particular kinds of thinking. In the Middle Ages, people thought symbolically.
When they saw an image of a fish or a loaf of bread, they thought of the most appropriate story in the Bible.
In this case, they thought of a passage in the Gospel of John: "Behold the Lamb of God, who taketh away our sins."
Vault Mosaic, Lamb and Angels, c. 532-47, St. Vitale, Ravenna