Marseillaise, mahr suh LAYZ, is the national hymn of France. Claude Joseph Rouget de Lisle, a French army engineer, composed the words and the music in Strasbourg on the night of April 25-26, 1792. He wrote the hymn as a marching song after France declared war on Austria and Prussia. Rouget de Lisle called his hymn "Song of the Rhine Army," in honor of the garrison to which he belonged.