Francis Bannerman was a prominent American businessman and arms dealer in the late 19th and early 20th centuries. He is best known for founding Bannerman's Castle, a military surplus business that specialized in selling surplus military goods and weapons. His company gained fame for its extensive inventory, which included everything from uniforms to artillery. Bannerman was born in 1851 in New York City and began his business after purchasing surplus goods from the U.S. Army. He eventually acquired a large estate on Pollepel Island in the Hudson River, where he built a castle to store his inventory. Bannerman's legacy continues to be remembered through his unique contributions to military surplus trade.