While we don’t know who wrote the lyrics for “The Marines’ Hymn,” we do know that the music was drawn from an opera, Geneviéve de Brabant, written by Jacques Offenbach. The French composer premiered his two-act opera in 1859. In 1867, he added a third act that included “Couplets des Deux Hommes d’Armes,” and it was this piece that provided the melody for “The Marines’ Hymn.”
The Marines’ Hymn is a serious, chest-thumping song, but Offenbach was best known for his comic operas, and Geneviéve de Brabant fits this description. In fact, the duet that was borrowed for “The Marines’ Hymn” is a comical number usually sung by a bass and baritone. Why this comic tune was selected for such a solemn purpose is unknown (mostly because we don’t know who first fit the words to music). The song was very popular in France when introduced in 1867, but who heard it, where they heard it, and when they heard it are Marine mysteries.