Jules Cécilien Jeannin

Jules Cécilien Jeannin (Marseille, 1866 – Hautecombe, Savoy, 1933) was a French musicologist whose work focused on liturgical chant and, above all, on the problem of rhythm in Gregorian chant. Trained at the conservatory in his native Marseille, his career combined practice as an organist with long-range scholarly research.

After his studies in Marseille, he joined the Benedictine abbey of Hautecombe in Savoy, where he served as organist. Between 1896 and 1898 he lived in the Middle East, a period during which he studied the liturgical chant of Catholic Syrians and Maronites. This research into Syrian music was apparently the first step in his investigation of the rhythm of Christian chant.

In his Etudes sur le rythme grégorien he defended a mensuralist approach against the equalist interpretation of the monks of Solesmes. His transcriptions, with bar lines of variable length, illustrate his central thesis: Gregorian chant is made up of short and long notes grouped into cells of variable extent, and the tonic accent of the word usually takes the place of the metrical accent.

His legacy is above all controversial and theoretical: his writings sparked debate about Gregorian rhythm, and his editions of Syriac and Chaldean liturgical melodies remain a reference point for his work on Eastern traditions.