born 0441; 990, Arezzo?
died 1050, Avellana?
Italian music theorist.
A Benedictine monk charged with training the choristers in the cathedral of Arezzo, he is credited with two important advances: the invention of the staff for notating exact pitches, and the use of different syllables to sing each pitch, or solmization . In his famous Micrologus (102633), he describes the use of at least a two-line staff and the use of syllables as a mnemonic device for singing musical pitches. The famous "Guidonian hand," an aid to modulation from one hexachord to another by using the joints of the hand to represent different pitches, is not mentioned in his extant writings.