semibreves

Semibreves are a basic note value used in medieval and Renaissance mensural notation. In the traditional hierarchy of long durations, they sit between the breve and the minim: a semibreve is longer than a minim but shorter than a breve. The exact length of a semibreve depended on the mensuration signs in effect at the time (the tempus and prolation), so its absolute duration varied across contexts, especially before the commonization of fixed modern time signatures.

In notation, a semibreve is typically written as a hollow oval note head, sometimes with or without stems depending on the period and style. In early white notation, the shape and ligaturing of semibreves were important for indicating rhythmic grouping and proportional relationships within polyphonic textures. The semibreve often served as a fundamental unit from which other note values were derived through mensural proportion.

Modern correspondence places the semibreve with the modern whole note, which in common time lasts four quarter-note beats. However, because medieval and Renaissance composers did not fix absolute durations in the same way as later notation, editors translating early music into modern notation may adjust values to reflect the original mensural relationships or use proportional notation to preserve the original sense of rhythm.

Etymology and usage: the term semibreve comes from Latin semibrevis, meaning “half-long” or “half-length,” reflecting its position in the sequence of longa, breve, semibreve, and minim. The term appears in various languages with minor spelling differences.