The most fierce passion is anger. In fact it is described as a boiling and stirring up of wrath against one who has given injury – or is thought to have done so. It constantly irritates the soul and above all at the time of prayer it seizes the mind and flashes the picture of the offensive person before one’s eyes. Then there comes a time when it persists longer, is transformed into indignation, stirs up alarming experiences by night. This is succeeded by a general debility of the body, malnutrition with its attendant pallor, and the illusion of being attacked by wild beasts. These four last mentioned consequences following upon indignation may be found to accompany many thoughts.
Evagrius Ponticus (345-399), The Praktikos 13