Guido d’Arezzo introduces a system for writing music: ut, ere, mi, fa, sol, la (the seventh note is missing: B); Guido d’Arezzo, as a mnemonic aid for the various pitches of the scale, suggests to his singers to use the first stanza of the hymn to Saint John by Paul the Deacon, using the first stanza of each verse: UT queant laxis – REsonare fibris – MIra gestorum – FAmuli tuorum – SOLve polluti – LAbii reatum – sancte johannes; the B will be added later, towards the end of the 15th century by the Spaniard Bartolomeo Ramos de Parej; finally, in the 17th century, the Ut (which is still used today in France), will become Do for us, thanks to Giovan Battista Doni.
