One of the most celebrated physicians and medical researchers of the ancient world, Galen of Pergamon, wrote a book about mental illness, called On Passions and Errors of the Soul. The passion considered most dangerous by Galen and other ancient writers is anger. That’s because anger is, in a sense, the most interpersonal of emotions. It poses a threat not only to the angry individuals themselves but to others around them, and even to society as a whole.
Galen’s most striking case study for anger is that of the Emperor Hadrian, who had a violent temper tantrum one day because an unlucky slave did something to annoy him. Hadrian was writing at the time and happened to have a stylus in his hand — the Roman equivalent of a fountain pen. In a moment of madness, he stabbed the slave right in the eye with it, blinding him. Later, when Hadrian had calmed down, and was feeling highly ashamed of himself, he summoned the man and asked what he could do to make amends. The slave was silent for quite a long time but eventually found the courage to speak frankly to the emperor: “All I want”, he said, “is my eye back.”
The consequences of anger are often very destructive. Sometimes they cannot be reversed. Even the most powerful man in the world may be unable to undo the harm he’s done in a fit of violent rage.