Daseian notation

Daseian notation (or dasian notation) is the type of musical notation used in the ninth century anonymous musical treatises Musica enchiriadis and Scolica enchiriadis. The music of the Musica enchiriadis and Scolica enchiriadis, written in Daseian notation, are the earliest known examples of written polyphonic music in history.[1]

Tu patris sempiternus es filius, written in Daseian notation. The Daseian signs are at the far left of the staff.