 A breve could theoretically be worth either three semi-breves or two in Franconian notation, but if worth two, one or the other would be doubled in length.There was no provision in this notation for equal duple division, which (along with imperfect tempus, therefore) would have to wait until de Vitry codified the concept of prolation in his "Ars nova" of 1322.By the 1280s, tripla (the top parts of motets and other polyphonic pieces) were moving more rapidly and independently than before, with the chant-based tenors becoming slower moving, supporting parts.