If you watched the last two episodes of Mercy Street, you saw the Knights of the Golden Circle (KGC) make an appearance. This secret organization was formed before the war and sought to extend a slave-based empire to territories that stretched around the Gulf of Mexico, down past Mexico and Central America to parts of South America, hence the circle. Its membership reached to every state in the Union and purportedly included the likes of Sam Houston, John Wilkes Booth, Jesse James, and William Quantrill.
