A brave person is usually said to "have liver". The liver in fact has always represented a symbol of courage and physical strength. For the ancient Greeks it was the seat of strength, stubbornness and passions, particularly of sensual love and anger.
There is also a myth on the subject, that of the Titan Prometheus who bravely stole fire from the gods to give it to men. Zeus, having discovered the theft, condemned him to be chained for eternity to a rock in the mountains of the Caucasus and arranged for a giant eagle to devour his liver every day. Every night, however, his liver grew back, so that the eagle could return to devour him the following day. In the myth there is a background of truth: the liver is the only organ of the human body capable of almost total regeneration. If, for example, in a surgical operation it is necessary to remove a part of it, within a few months the body is able to totally reintegrate it.