The earliest evidence can be found in an older Troper-Proser with libellum structure (F-Pn lat. 1120). In some late additions cantors made exemplifications of a polyphonic performance of organum similar to those additions in the Gradual of the Abbey of Saint-Maur-des-Fossés (F-Pn lat. 12584, fol. 306). Under Cluniac influence the latter abbey developed an extravagant liturgy since 1006, when it was ruled by a new Abbot, who was sent from Cluny, where he had served as a cantor. The polyphony can be easily recognized, because the notator used a method similar to a modern score.