Guido Aretino

Guido Aretino, of Arezzo, a Benedictine monk, who is credited with the invention of counterpoint, flourished in the 11th century. Experts consider it certain that he designed the construction of the stave, and probable that to him is due the discovery of the hexachord, solmisation, and the Harmonic Hand. Guido, who was invited to Rome by two Popes, left works entitled Micrologics and Antiphonariitm on musical theory.