LSE4113084 Portrait of Guido d?'Arezzo (Gui or Guy d?'Arezzo), Italian benedictine, music theorist (990-1050) and one of the founders of the musical range. Engraving in ??sHistory of the Popes??????, 19th century. by French School, (19th century); Private Collection; (add.info.: Portrait of Guido d?'Arezzo (Gui or Guy d?'Arezzo), Italian benedictine, music theorist (990-1050) and one of the founders of the musical range. Engraving in ??sHistory of the Popes??????, 19th century.); Photo ?? Leonard de Selva; French, out of copyright.