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)
Clavier-Übung III we trust, Protect Christ's congregation, His everlasting truth assert, All evil graciously avert, Lead us to life eternal.</poem> BWV 675, 66 bars long, is a two-part invention for the upper and lower voices with the "cantus firmus" in the alto part. The two outer parts are intricate and rhythmically complex with wide leaps, contrasting with the "cantus firmus" which moves smoothly by steps in minims and crotchets. The time signature has been taken to be one of the references in this movement to the Trinity. Like the two preceding chorale preludes, there is no explicit "manualiter" marking, only an ambiguous