Hilarión Eslava was a theoric, editor, teacher and composer. He was a choirboy in the Pamplona Cathedral, and at his 17 served as a violinist. He studied the piano, organ, violin and composition. He was maestro de capilla at Burgo de Osma, the Royal Chapel in Madrid and Sevilla’s Cathedral. He took holy orders but he had ecclesiastical opposition to his secular operas. These three opere serie (all lost) were all written to Italian librettos and in the Italian style. His operatic religious music had an Italian style. He worked as professor of composition at the Madrid Conservatory and in 1866 became its music director. His most popular works were the Lira sacro-hispana (an anthology of sacred Spanish vocal music) and his manuals on composition.