When transcribing mensural music, an incipit at the beginning of the
piece is useful to indicate the original key and tempo. While today
musicians are used to bar lines in order to faster recognize rhythmic
-patterns, bar lines where not yet invented during the period of
+patterns, bar lines were not yet invented during the period of
mensural music; in fact, the meter often changed after every few
notes. As a compromise, bar lines are often printed between the
staves rather than on the staves.