Guido of Arezzo

Guido of Arezzo was an Italian music theorist and pedagogue of High medieval music. A Benedictine monk, he is regarded as the inventor—or by some, developer—of the modern staff notation that had a massive influence on the development of Western musical notation and practice. Perhaps the most significant European writer on music between Boethius and Johannes Tinctoris, after the former's De institutione musica, Guido's Micrologus was the most widely distributed medieval treatise on music.

Biographical information on Guido is only available from two contemporary documents; though they give limited background, a basic understanding of his life can be unravelled. By around 1013 he began teaching at Pomposa Abbey, but his antiphonary Prologus in antiphonarium and novel teaching methods based on staff notation brought considerable resentment from his colleagues.