Sir Henry Morton Stanley, I presume.

From my research this is Henry Morton Stanley. He joined the Confederates and fought at Shiloh. After captured he joined the Union. He was born John Rowlands in Wales and took the Stanley name upon arriving in US. He became famous as Sir Henry Morton Stanley, the famous for his exploration of Africa and his search for David Livingstone. Stanley is often remembered for the words uttered to Livingstone upon finding him: "Dr. Livingstone, I presume?".