Modus (medieval music) "tempus" (corresponding to the modern concept of a measure or bar and referring to the division of "breves" into two or three "semibreves") and "prolatio" (the division of "semibreves" into two or three "minims"). The "modus longarum" was applied primarily to pieces based on a cantus firmus tenor part in long note values. An even longer temporal unit was the "modus maximarum", but it is of little practical importance outside of the 13th century . Modus (medieval music) In medieval music theory, the Latin term modus (meaning "a measure", "standard of measurement", "quantity", "size", "length", or, rendered in English, mode)
Mensural notation and short notes (minims and crotchets), or groups of three short notes. In the 13th century, all of these were notated using only the longa and breve notes. A longa was automatically understood to fill a whole ternary metric group whenever it was in the neighborhood of other notes that did the same, i.e., whenever it was followed either by another longa or by a full group of three breves. When, however, the longa was preceded or followed by a single breve, then both filled a ternary group together. Thus, the longa had to be reduced to a value of