The hormasia-table is preserved in a manuscript from 1040 ad. The heart or kernel of the table (two columns, each with 16 Hypolydian notes) was probably established in antiquity in order to provide a mean-tone tuning and a basic system for playing two voices on the harp (or the organ): a given melody with the right hand and a more or less schematic accompaniment with the left. In Byzantine times, the system was probably used as a stringing plan for doubly registered psalteries, both of the rectangular and the harp-like type.
NajockD. (2006) Die Musiklehre des Boethius: Schlußstein der antiken Theorie und Grundstein für das Mittelalter. In: R.F.Glei ed. Die Sieben Freien Künste in Antike und GegenwartTrier: Wissenschaftlicher Verlag pp. 115-140.