PROLATION (Lat. Prolatio; Ital. Prolazione). A subdivision of the rhythmic system, which, in Mediæval Music, governed the proportionate duration of the Semibreve and the Minim.
Prolation was of two kinds, the Greater, and the Lesser—called by early English writers, the More, and the Lesse, and by Italians, Prolazione Perfetta, and Imperfetta. In the former— usually indicated by a Circle, or Semicircle, with a Point of Perfection in its centre—the Semibreve was equal to three Minims. In the latter—distinguished...