​BREVE (Fr. Carrée; Ital. Breve). A note of the value of two semibreves, rarely met with in modern music, in which there is no place for it, as the longest bar commonly used (viz. a bar of 12-8 time) has but the value of a semibreve and a half. Although now nearly obsolete from its great length, the breve was originally (as indicated by its name, derived from brevis, short) the shorter of the two notes of which the earliest measured music, invented about A.D. 1200, was composed. These two notes, which corresponded to the long and short syllables of the text to which they were sung, were termed longa and brevis, and were written thus, and . The proportion which they bore to each other was not always constant, the longa containing sometimes three breves, in which case it was called perfect, and sometimes only two, when it is said to be imperfect. So likewise, after the introduction of a still shorter note called semibrevis, the brevis could be either perfect or imperfect, and consist of three or two semibreves. These variations of proportion, which, together with many others, remained in use until about the middle of the 17th century, and which could not but have added immensely to the difficulty of the study of music, were dependent on the order in which the longer and shorter notes followed each other, and also upon the appearance of certain time-signatures which were placed at the beginning of the composition. For a full account of these the reader is referred to Bellermann's treatise 'Die Mensuralnoten und Taktzeichen des 15. und 16. Jahrhunderts,' Berlin, 1858.

The breve, together with other notes belonging to the same epoch, was originally written black, the more modern white notes (Fr. blanches) written in outline being introduced by Dufay about the end of the 14th century. After this period black notes (Fr. noires) were exclusively used to express diminution, the note made black losing a portion of its value, either one-third or one-fourth, according to circumstances. A relic of this custom survives in modern music in the method of writing minim and crotchet.

In modern music the breve, in the rare cases in which it is used, is always written white, and either of an oblong form, thus , or oval with two small vertical strokes at each end, thus .

The expression alla breve, placed at the commencement of a composition, has been variously interpreted. Some have understood it to mean a rhythm of one breve to a bar, while others, translating the words 'alla breve' literally into 'in short fashion,' understand by it a rhythm of either two or four beats in a bar, but at a double rate of movement, semibreves being taken at about the speed of ordinary minims, and so on. In favour of this latter view is the fact that the signature of alla breve time is always the semicircle crossed by a vertical stroke, , which is the 'diminutio simplex in tempus imperfectum' of the ancient measured music, where it served precisely the same purpose, i. e. by reducing each note to half its proper value it doubled the rate of movement. Both views agree in the most important particular, namely, that compositions marked 'alla breve,' or, even when not so marked, if provided with the distinctive time-signature, must be performed twice as fast as if simply marked with the sign of common time, or 4-4. And with regard to the opinion which holds that compositions alla breve ought to be written in bars of the value of a breve, it may be urged that in spite of the undoubted fact that most of such compositions have but one semibreve in the bar, it is possible that this method of writing may have been intended to represent merely the division of the original alla breve bar into two halves, for convenience of reading, a division which has actually been made in certain cases, as for example in Handel's chorus 'All we like sheep' [App. p.564 "'And with his stripes'"] (Messiah), which was originally written in bars of the value of two semibreves, and marked 'alla breve,' although now printed in bars of half that length. Moreover, it is certain that the expression alla breve has never been applied to movements in triple time, although if it had had reference merely to ​the rate of movement this would have been perfectly possible.