11. Like other calculating devices of the period, the Organum prefigures modern computing technology. 12. The Organum Mathematicum was a box or chest divided into nine or more compartments. 13. Anonymous IV mentions L�onin and P�rotin as the best composers of organum and discant respectively. 14. On folio 81r and 105r we have three early examples of later added florid organum . 15. On folio 105 recto, a �Benedicamus domino?was notated separately from the florid organum . 16. This was used to notate organum in two, three and four-voice styles. 17. BWV 671 is a chorale motet for " organum plenum " and pedal. 18. The Organum can be thought of as an improved and generalized version of the Arca. 19. The earliest European sources of information concerning organum regard it as a well-known practice. 20. Whatever its origin, singing in parallel fifths became commonplace in early organum and conductus styles.
