Offering his services as well as those of his legion, General Shelby found no takers.
At the end of the American Civil War, an enitre brigade of mixed cavalry led by General JO Shelby refused surrender and escaped to Mexico. The reception in Mexico was less encouraging than they expected. Mexico at the time was occupied by French troops who propped up an Austrian emperor, Maximilian, over an issue of defaulted national debt. Mexican insurgents Benito Juarez were in open combat with the French army of occupation. General Shelby met with both sides on his trip through the country and offered his legion of nomads up for service to either side that would accept. Guided towards Mexico City after helping a French unit against guerillas Shelby met with the Austrian pretender, Maximilian, in person. Maximilian, declining to employ such a large body of men with such questionable loyalty, declined wholly Shelby's offer. The Austrian pretender placed his trust in his French troops and the few Mexicans loyal to his court.
This meant the end of the line for the Iron Brigade. Shelby had already sunk their flag at the border and sold their artillery (to a Mexican warlord fighting against Maximilian for the sum of $16,000). The Iron Brigade's treasury was divided evenly among the men, with each receiving about $50 regardless of rank. The men were allowed to take their horse, arms and all of their equipment, paroled from the service at last more than five months after Lee's surrenders. The men scattered in a hundred directions. Most returned back to their occupied homeland. Some took advantage of their new home and settled in Mexico. The lure of gold and a new start drew some of them to the west. It is known that many of the veteran soldiers joined the Third Zouaves of the Imperial French Army, a crack unit of tough professional soldiers from all over the world stationed in Mexico. The unit would be recalled to France following their evacuation from Mexico in 1866 only to be obliterated at the Battle of Gravelotte during the Franco Prussian war three years later with several of the confederate die hards still on the rolls.
In Missouri, many influential citizens held General Shelby in the highest esteem and referred to him as the greatest Missouri soldier of the Confederacy. On his return from his self imposed exile in Mexico in 1866 he was hailed and treated as a hero. He was appointed the 11th United States Marshal for the Western District of Missouri in 1893, a position that he held until his death in Bates County, Missouri in 1898. Maximilian would never make it out of his kingdom, being shot by Juarist troops in 1867. Although he bribed the seven riflemen not to shoot him in the face, one did anyway. Maximilian’s body was embalmed and displayed publicly in Mexico before being buried in the Imperial Crypt in Vienna, Austria, early the following year.
In tribute to both the no less than three civil war Union Infantry units all known as the Iron Brigade and General Shelby’s unit; the 4000-man Second Brigade Combat Team of the US Army's First Armored Division has carried the Iron Brigade moniker since 1985. It is currently home stationed in Baumholder Germany. On November 10, 2006 they deployed back to Iraq for a second time after completing an epic 15 combat month tour in 2004.
Source - General JO Shelby-Undefeated Rebel
Daniel O'Flaherty. 1954- UNC Press