Mensural notation recoverable from the modern text. While 19th and early 20th century editions of Renaissance music often preserved the large note values of the originals, including breves and longs, most modern editions will use scaled-down note values in order to match modern reading habits regarding tempo and beat structure. For 16th century music, a frequent scheme is diminution by a factor of 2 (i.e., rendering semibreves as modern minims), in a modern "alla breve" bar. Older music might be diminished by a factor of 4 (rendering semibreves as crotchets) or sometimes 8 (rendering breves as crotchets). For 13th-century pieces, diminution by
Note value duration, as at the end of a piece (e.g. at the end of Mozart's Mass KV 192). A single eighth note, or any faster note, is always stemmed with flags, while two or more are usually beamed in groups. When a stem is present, it can go either up (from the right side of the note head) or down (from the left side), except in the cases of the "longa" or "maxima" which are nearly always written with downward stems. In most cases, the stem goes down if the notehead is on the center line or above, and up otherwise.