Prolation Prolation Prolation is a term used in the theory of the mensural notation of medieval and Renaissance music to describe its rhythmic structure on a small scale, as opposed to "tempus", which described a larger scale. The term "prolation" is derived from the Latin "prolatio", first used by Philippe de Vitry in describing Ars Nova, a musical style that came about in 14th-century France. Prolation, together with tempus, corresponds roughly to the concept of time signature in modern music. Prolation describes whether a semibreve (whole note) is equal in length to two minims (half notes) ("minor prolation" or "imperfect prolation";
Note value Note value In music notation, a note value indicates the relative duration of a note, using the texture or shape of the "note head", the presence or absence of a "stem", and the presence or absence of "flags/beams/hooks/tails". Unmodified note values are fractional powers of two, for example one, one-half, one fourth, etc. A rest indicates a silence of an equivalent duration. The breve appears in several different versions, as shown at right. The first two are commonly used; the third is a stylistic alternative. Sometimes the longa or breve is used to indicate a very long note of indefinite