The sign placed at the beginning of a staff to denote the pitch of one (and hence others) of its lines or spaces. They were first systematically used in 11th-century liturgical manuscripts. Letters denoting F and c were the most common; the g came increasingly into use in the 15th century. The F and g clefs have come to be known as the ‘bass clef’ and ‘treble clef’ respectively, in their normal situations on the fourth line up (for the bass) and the second line up (for the treble); the c clef, according to its placing, may be called the soprano clef (on the bottom line), or moving upwards, the mezzo-soprano, the alto, the tenor and the baritone.
