Sir Arthur Seymour Sullivan was an English composer. He is best known for 14 comic opera collaborations with the dramatist W. S. Gilbert, including H.M.S. Pinafore, The Pirates of Penzance and The Mikado. His works include 24 operas, 11 major orchestral works, ten choral works and oratorios, two ballets, incidental music to several plays, and numerous church pieces, songs, and piano and chamber pieces. His hymns and songs include "Onward, Christian Soldiers" and "The Lost Chord".