A castrated man in the ancient world was called a eunuch. His castration usually occurred early in life, typically without consent, before testosterone could virilize his body during puberty. Testosterone production increases dramatically in puberty and is required for the development of the masculine characteristics of the male body, such as voice deepening, body hair growth, muscle development, libido, and genital enlargement. Although some testosterone is still produced in the adrenal glands, the main source was gone for eunuchs entering puberty and therefore they would’ve lacked such characteristics. Even in adulthood, eunuchs would have looked more like large boys than men.
Lack of testosterone also reduces aggression and erectile function, making eunuchs ideal for managing harems, which is where the term eunuch originated (eune means “bed” or “harem;” echo means “hold” or “have”). Eunuchs also served as guards and servants within their master’s bedrooms, with duties such as bathing and dressing royalty. Across Europe in the Middle Ages, castrati (Latin) were valuable in choirs for their high-pitched voices.
Eunuchs were usually slaves that lacked loyalties to the military, royalty, or a family of their own and were therefore viewed as trustworthy servants with little interest in their own dynasties. Many ancient empires employed them, often castrating boys taken as prisoners of war. Some eunuchs, however, were self-castrated for religious purposes. Furthermore, the term “eunuch” could also refer to a non-castrated but impotent or celibate man.