Rhythms in which long notes alternate with one or more short notes, so called because the long notes are usually written with the aid of the dot of addition (see Note values). Dotted rhythms are found in mensurally notated music of all periods; this article, however, deals mainly with music of the 17th and 18th centuries, in which it was customary to alter certain sorts of written rhythmic values in performance (see also Notes inégales; for notational meanings of the dot before 1600 see Notation, §III). The principal issue is the degree to which such rhythms sounded uneven, rather than the specific manner of their notation (e.g. the dot may be replaced by a rest or tie).
Dozens of contemporary theoretical and pedagogical sources indicate that the dot was ordinarily equal to one half the value of the note or rest preceding it, just as it is today. But the treatises also present various exceptions. The dot could stand for a tie (...