On April 6, 1860, a corespondent for the New Orleans Crescent reported from Brownsville:
"This section of the country is ﬁlled with members of this mysterious organization, and their camp ﬁres are increased every night by new parties arriving during the day. The road is dusty with their constant movement, and from this place to Goliad it is said there is a continuous caravan of them, coming in small parties and large parties, on horseback and in wagons, armed and unarmed, with money and without it."
The "mysterious organization" was the Knights of the Golden Circle, whose goal was to create a slave empire with its geographic center in Havana and extending 1200 miles in all directions.
This "Golden Circle" would extend as far north as Maryland and as far south as Columbia. It would encompass the entire Gulf of Mexico and the Caribbean.
According to the communique that brought them to the Rio Grande, their mission was to "make 58 of 2." If you had a copy of their decoder sheet, known as The Key to Degree Work, you would know that 58 meant "a slave state" and 2 meant "Mexico."
A coded KGC message from 1861
They were not alone in this project. There was help on the other side of the river. The governor of Guanajuato had agreed to provide 16,000 men to serve under KGC officers.
The object was actually to to turn Mexico into 25 slave states and get them admitted to the union. That would mean 50 new Southern senators and 60 representatives in Washington. The slave holding agricultural states of the South would then be able to politically dominate the industrial North.
But don't think we are only talking about black slavery. Another stated goal this mission was to change 88 (the Mexican peon system) into 89 (perpetual slavery). No race was to be exempt. The Golden Circle would be a rainbow of servitude.
The army on the border swelled through early April...then gradually deflated like an old party balloon. The money, weapons and leadership for the mission never arrived from New Orleans.
Unknown to the men on the Rio Grande, an impostor had been traveling about the South impersonating the group's leader, George W. Bickley, and collecting donations. The leadership was sent into disarray when the New Orleans Picayune denounced the real Bickley, then headquartered in that city, as an impostor.
The KGC regrouped, rallied and attempted to make another go of the Mexican invasion that fall. But Lincoln's election in November turned their eyes towards home as the Southern states, one by one, seceded.
The Knights of the Golden Circle and their dreams of a slave empire where swallowed whole in the coming conflagration.