Allan Pinkerton was a Scottish-American cooper, abolitionist, detective, and spy, best known for creating the Pinkerton National Detective Agency in the United States and his claim to have foiled a plot in 1861 to assassinate president-elect Abraham Lincoln. During the Civil War, he provided the Union Army – specifically General George B. McClellan of the Army of the Potomac – with military intelligence, including extremely inaccurate enemy troop strength numbers. After the war, his agents played a significant role as strikebreakers – in particular during the Great Railroad Strike of 1877 – a role that Pinkerton men would continue to play after the death of their founder.

George Brinton McClellan was an American military officer and politician who served as the 24th governor of New Jersey and as Commanding General of the United States Army from November 1861 to March 1862. He was also an engineer, and was chief engineer and vice president of the Illinois Central Railroad, and later president of the Ohio and Mississippi Railroad in 1860.