VEN5027260: Solfege: page of a codex representing the Guidonian hand. The hand of Guido d'Arezzo (Gui or Guy d'Arezzo) is a method of recording notes used during singing and accompanying solmisation, a study of the song founded by Guido d'Arezzo at the end of the 11th century. Manuscript from the end of the 15th century. Musical Bibliographic Museum of Bologna. Italy / Bridgeman Images