Castrato is a male singer castrated before puberty to preserve a high voice — the dominant operatic vocal type of the baroque era.
From the late 16th to the early 19th century, the Italian church and opera house relied on castrati: boys whose voices were preserved by surgery before puberty, producing adult singers with the lung capacity of men and the vocal range of women. The Vatican choirs employed them; Baroque opera was structured around them. The most famous, Farinelli (Carlo Broschi, 1705–1782), commanded astronomical fees and ten years of King Philip V of Spain's exclusive service, singing the same four arias to the melancholic monarch every night. Handel wrote heroic roles for castrati like Senesino and Caffarelli. The practice was always quietly deplored and slowly ended: the last operatic castrato died in the 1860s, and the Vatican's Sistine Chapel choir retained one castrato singer until 1913. Today their roles are sung by countertenors or mezzo-sopranos. The vocal type is gone, but the music written for it survives.