A Dictionary of Music and Musicians/Canto Fermo

CANTO FERMO, or CANTUS FIRMUS, the plain song—as distinguished from Canto figurato, the florid or figured song—is the simple unadorned melody of the ancient hymns and chants of the church. Such tunes are often employed by the great church composers of the Roman church as the basis of their compositions. Thus in Palestrina's masses 'Æterna Christi munera,' and 'Assumpta est Maria,' each movement begins with the first phrase of the hymn. His motet 'Beatus Laurentius' is still more completely founded on the canto fermo, since the tune is sung throughout the piece in the first tenor, while the other four parts are moving in counterpoint above and below it—a counterpoint more or less closely modelled on the tune. In such cases the tune is usually marked in the score as C. F. (canto fermo). Bach treats his choral-melodies in the same way (see his cantata 'Ein' feste Burg'; his organ 'Vorspiele' on 'Kyrie'; 'Christe'; 'Kyrie'; on 'Allein Gott'; 'Dies sind die heiligen'; 'Vater unser,' etc., etc.), and in so doing styles them 'canti fermi.' In English the term is often translated by 'Plain-chant.'

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