The monochord is the central instrument of harmony. This applies both in terms of history and content. Historically, the monochord goes back to the traditions of Pythagoras (~ 570 – 510 BC). Neither himself nor his contemporaries have written evidence of this.
Only in the time of the Roman emperors the Neo – Platonists, for example Jamblichus of Chalkis (about 240/245 – 320/325), picked up again life and work of Pythagoras in traditional writings
Music theorists in the Middle Ages refer to this, such as Franchino Gaffurio (1492 – 1480?). In his writing appear images that depict Pythagoras when working on the Monochord.