Sir Arthur Seymour Sullivan (May 13, 1842 – November 22, 1900) was an English composer.
He is best known for his series of 14 operatic collaborations with the dramatist W. S. Gilbert, including such enduring works as H.M.S. Pinafore, The Pirates of Penzance and The Mikado. Sullivan composed 23 operas, 13 major orchestral works, eight choral works and oratorios, two ballets, incidental music to several plays, and numerous hymns and other church pieces, songs, and piano and chamber pieces. The best known of his hymns and songs include “Onward Christian Soldiers” and “The Lost Chord”.