Male soprano or alto voice produced as a result of castration before puberty. The castrato voice was introduced in the Vatican's Sistine Chapel in the 16th century, when women were still banned from church choirs as well as the stage. It reached its greatest prominence in 17th- and 18th-century opera. The illegal and inhumane practice of castration, largely practiced in Italy, could produce a treble voice of extraordinary power, attributable to the lung capacity and physical bulk of the adult male. The unique tone quality and the ability of intensively trained singers to execute virtuosic passagework made castrati the rage among opera audiences and contributed to the spread of Italian opera. Most male singers in 18th-century opera were castrati; the most famous bore the stage names Senesino (Francesco Bernardi; died c. 1750), Caffarelli (Gaetano Majorano; 1710–1783), and Farinelli. Castrati sang in the Sistine Chapel choir until 1903.