The present article addresses the topic of emotions in the context of military action. Fear and anger are considered to be the most common of these emotions. The chivalric ethics developed in the Middle Ages promoted restraining brutality and cruelty in warfare, especially towards the captured enemy, as the propagated ideal of the knight required showing mercy to the defeated. Such examples can be found during the Hundred Years’ War, when the chivalric ethos had a significant influence on the display, perception, and assessment of emotions experienced by soldiers. However, towards the end of the Middle Ages, chivalric culture faced many challenges and underwent significant changes. The erosion of the chivalric ethos became most evident during the War of the Roses, when personal hatred between the two pretenders to the throne and personal vendetta, as well as the use of fear as an instrument of political pressure played a significant role in the final outcome of the conflict.