A castrated human male. Eunuchs were used as guardians of harems in ancient China and in the Persian empire of the Achaemenids and also at the courts of the Byzantine emperors and the Ottoman sultans. They became the friends and advisers of the rulers of these powers, as they did of Roman emperors. Castration was also imposed as a form of punishment (Abelard suffered in this way); was practised voluntarily by some Christian sects (the most notable Christian eunuch being the theologian Origen); and was used to produce male adult sopranos in Italy—castrati—until Pope Leo XIII banned the practice in 1878.