Contratenor
A countertenor (or contra tenor) is a type of classical male singing voice whose vocal range is equivalent to that of the female contralto or mezzo-soprano voice types, generally extending from around G3 to D5 or E5, although a sopranist (a specific kind of countertenor) may match the soprano's range of around C4 to C6. Countertenors often are baritones or tenors at core, but rarely use this vocal range in performance.
The term first came into use in England during the mid-17th century, and was in wide use by the late 17th century. However, the use of adult male falsettos in polyphony, commonly in the alto range, was common in all-male sacred choirs for some decades previous, as early as the mid-16th century. Modern-day ensembles such as The Tallis Scholars and The Sixteen maintain the use of male altos in period works. During the Romantic period, the popularity of the countertenor voice waned and few compositions were written with that voice type in mind.
In the second half of the 20th century, there was great interest in and renewed popularity of the countertenor voice, partly due to pioneers such as Alfred Deller, as well as the increased popularity of Baroque opera and the need of male singers to replace the castrati roles in such works. Although the voice has been considered largely an early music phenomenon, there is a growing modern repertoire.
In polyphonic compositions of the 14th and early 15th centuries, the contratenor was a voice part added to the basic two-part contrapuntal texture of discant (superius) and tenor (from the Latin tenere which means to hold, since this part "held" the music's melody, while the superius descanted upon it at a higher pitch). Though having approximately the same range as the tenor, it was generally of a much less melodic nature than either of these other two parts. With the introduction in about 1450 of four-part writing by composers such as Ockeghem and Obrecht, the contratenor split into contratenor altus and contratenor bassus, which were respectively above and below the tenor. Later the term became obsolete: in Italy, contratenor altus became simply altus, in France, haute-contre, and in England, countertenor. Though originally these words were used to designate a vocal part, they are now used to describe singers of that part, whose vocal techniques may differ (see below).
...
Wikipedia