Who is George Washington Williams from King Leopold's Ghost and what is their importance?

George Washington Williams (1849 - 1891) was a minister and historian. A veteran of the American Civil War, he subsequently traveled to Mexico and enlisted in the armed forces, participating in the overthrow of Emperor Maximilian. He was commissioned a lieutenant but later received the honorary title of colonel—he thereafter affected the rank. Additionally, he claimed to have an advanced collegiate degree and usually presented himself as if he were on some type of secret appointment for a powerful political figure. None of this was true. Williams abandoned a wife and children and then traveled to Europe.