The castrati were male singers, picked out as boys, with exceptional voices. Their high soprano or alto voices were preserved by an operation when they were between the ages of seven and ten; various methods were used, but the most common was to sever the spermatic ducts, causing the testes to atrophy. The resulting hormone imbalances produced an unusual height and a greatly expanded ribcage, allowing a breath control which apparently gave them voices of exceptional power and technique. Since their vocal chords remained flexible and unthickened, they preserved their soprano or alto range. The operation was never officially legal, and the castration was usually attributed to 'accidents'.

	The Heyday of the Castrati

Much of the Italian music of the 17th and especially the 18th Century was written for castrato singers. In church music, especially in the conservative Papal States, women were expected to be silent, so the soprano and alto lines were sung by castrati. In opera, the most popular genre was Opera Seria, with elevated characters and an emphasis on solo singing, where high voices were thought to be more suitable to represent the importance of kings and heroes. By the mid-18th Century, Italian opera was popular all over Europe, and the castrato stars like the soprano Farinelli¹ were rich and famous. Tall and often handsome, they had many female admirers, and one, Tenducci, managed to marry in spite of opposition from his wife's family.

	Some Castrato Roles

While most Opera Seria works were by Italian composers, those remembered nowadays are mostly by German composers under Italian influence. Handel's operas with castrato heroes included Giulio Cesare (1724), Tamerlano (1724), and Rodelinda (1725). Another famous castrato role was Orfeo in Gluck's Orfeo ed Euridice (1762). In 1781, towards the end of Opera Seria's popularity, Mozart wrote the role of Idamante in Idomeneo for a soprano castrato, but replaced him with a tenor in the revised version of 1786. Both Rossini (1813) and Meyerbeer (1824) wrote parts for the soprano Velluti, the last important castrato star, who retired in 1830.

	What Did They Really Sound Like?

No one knows what the best castrati sounded like. Some recordings of Moreschi (see below) survive from the early 20th Century, but they are not good enough to give an idea of how Farinelli or Velluti actually sang. Contemporary accounts used descriptions like 'supernaturally beautiful' and 'seraphic', suggesting a quality which simply may not exist today.

	Changing Times

The French Revolution brought many changes in European attitudes, and the opera-going public turned against the idea of castrati. Composers no longer gave their heroes soprano or alto voices, and the castrati began to disappear from the operatic stage by the 1820s. They survived longer singing church music; the last Italian castrato singer, Alessandro Moreschi, was the director of the Sistine Chapel choir and died in 1922.

	Who Should Sing Their Music Today?

Mostly neglected through the 19th and early 20th Century, the Opera Seria works of composers like Handel are becoming increasingly popular. A problem arises when considering any role originally sung by a castrato. It can be sung by a woman, but this may give a jarring effect for the audience, if the appearance of the hero and the timbre of the voice are obviously female. The part can be transposed down for a tenor or bass, but that changes the balance of the music and is anathema to musical purists. Finally, the parts can be sung by counter-tenors. A counter-tenor is a man with a normal voice who sings soprano or alto in falsetto. A revival of counter-tenor singing has produced singers like Jochen Kowalski and Andreas Scholl whose voices have the power and emotion to present the castrato roles successfully on the operatic stage.