(Lat.: ‘propriety’).
A term used in theoretical writings on mensural music from the mid-13th century onwards. It refers to a quality of ligatures that depended on the value of the first note of the ligature. The first note was normally assumed to be a breve unless its normal shape was modified. If the first note was of normal shape (for an ascending ligature this meant without stem, for a descending ligature this meant with a stem descending to the left) then the ligature had propriety and the first note was a breve. If the ascending ligature began with a note with a stem descending to the right, or if the descending ligature began with a note without a stem, then the ligature had no propriety and the first note was a long. Ligatures cum opposita proprietate were a special case, written with a stem ascending to the left, where the first two notes of the ligature were always understood to be semibreves. A quality of ligatures that depended on the value of the final note of the ligature, perfectio (‘perfection’), was governed by similar rules. For the usual shapes for two-note ligatures see Perfectio, Table 1. Ligatures of three, four and more notes were governed by the same rules, with all but the first and last notes understood to be breves (except in the case of opposite propriety, when the second note was always a semibreve, or where a note is graphically distinguished as a long or a maxima).
See also Ligature (i); Notation, §III, 2(viii) and 3(ii); and Rhythmic modes.
F. Reckow: ‘Proprietas und Perfectio: zur Geschichte des Rhythmus, seiner Aufzeichnung und Terminologie im 13. Jahrhundert’, AcM, xxxix (1967), 115–43
W. Frobenius: ‘Proprietas’ (1973), HMT