Longa (music)

The number of breves in a long was determined by the "modus" or "mode" of a passage.

Imperfect longs, worth two breves, existed in perfect mode from the earliest sources (late 12th century), while the fourteenth century saw the introduction of perfect longs, worth three breves, in imperfect mode through the use of dots of addition (puncti additiones).

[citation needed] Prior to the innovations of Franco of Cologne in the mid-thirteenth century, the value of the longa was in common usage in both theoretical and practical sources but appeared primarily in pre-mensural notation ligatures, symbols representing two or more notes joined together.

As a result, there were four possible ligature types: those beginning with a brevis and ending with a longa, which had both propriety and perfection; the reverse, which had neither; those both beginning and ending with a longa, which lacked propriety but had perfection; and those beginning and ending with a brevis, which were proper but not perfect.

Over the course of the fifteenth century, the void notehead (shown in the image above) became the norm.