Sir Arthur Seymour Sullivan was an English composer, best known for his collaboration with librettist W.S. Gilbert. Together, they created a series of comic operas that have become enduring classics, including "H.M.S. Pinafore," "The Pirates of Penzance," and "The Mikado." Sullivan's music is characterized by its catchy melodies, lively rhythms, and clever orchestration. He also composed a wide range of other works, including hymns, orchestral pieces, and ballet music. Sullivan was knighted for his contributions to music and is remembered as one of the most influential composers of his time.