The Ars Nova of the early 14th c. is a heavily contested in musical scholarship. Among pressing questions are: (1) the almost complete disappearance of musical sources in 1310-1350; (2) the connection between Ars Nova and Ars Antiqua: continuity or rupture? (3) the mysterious figure of Jacobus of Liège, (4) the date of his treatise Speculum musicae, (5) the meaning of the Papal bull Docta sanctorum, (6) the emergence of counterpoint. In the midst of all this, (7) Machaut steps forward, around 1350, with a substantial musical repertoire in a fully-developed new style. Nothing here makes sense. Or does it?