[1] Shelby's Iron Brigade was originally formed in 1863, under orders from Major General Thomas C. Hindman, following a successful recruiting expedition into Missouri by Joseph O. Shelby, Upton Hays and John T. Coffee, who each recruited a regiment of cavalry.

The brigade remained in Shelby's Division in the Army of Missouri and fought in Maj. Gen. Sterling Price's Missouri Expedition in 1864—saving Price's army from destruction several times, including the retreat at the Battle of Marmiton River.

[3] In the autumn of 1864, some 1,500 of Shelby’s Iron Brigade cavalry surrounded Sedalia, Missouri and overpowered local Union militia defenders.

[5] Later, the Missouri Iron Brigade distinguished themselves at the 1864 battles of Little Blue River and Westport, and captured many towns from their Union garrisons, including Potosi, Boonville, Waverly, Stockton, Lexington, and California, Missouri.

[citation needed] Rather than surrender in 1865 with the collapse of the Confederacy, Shelby and his men rode south into Mexico in June, where they offered their services to Emperor Maximilian, who declined to accept the ex-Confederates into his armed forces.