In fall 1861, John R. Baylor first conceived the idea to form a brigade of cavalry to conquer the southwestern territories for the Confederacy.

[1] In May 1862, the Confederate States Army empowered Baylor to organize five battalions of Partisan Rangers of six companies each.

[2] Henry Hopkins Sibley dismissed Baylor and appointed Peter Hardeman as the battalion's commander.

It camped at Victoria, Texas, from summer 1862 to April 1863, part of the time under the temporary leadership of William Polk Hardeman.

The unit, now a full regiment, joined Richard Montgomery Gano's cavalry brigade in the Indian Territory.