Waul's Texas Legion was organized at Brenham, TX, during the summer of 1862, with a cavalry battalion and infantry regiment. Almost from the beginning, the cavalry battalion of six companies was separated from the infantry. The battalion, also known as, Willis' Battalion of Texas Cavalry, was assigned to the Dept. of MS and East LA, and later to the cavalry command of Gen. Nathan B. Forrest. The battalion saw action under Generals Forrest and Hood, and was active in MS, TN, KY, and GA.

In August 1999 a Centennial Memorial was held in honor of Colonel Willis and his wife, Caroline Jane "Carrie" (Mooney) buried beside him. A wreath of the Texas State Flower, the Bluebonnet, was be placed at the grave of Colonel  and Mrs. Willis. A Yellow Rose of Texas rosebush was planted at their graves and watered with water from the Guadalupe River in Gonzales Co., TX, where Leonidas formed his cavalry unit. This river runs near the old family ranch. Soil was sprinkled over the graves - soil from the Brenham area at Washington-on-The-Brazos in Washington Co., TX, where young Captain Leonidas Willis trained his cavalry unit in Waul's Texas Legion.

On October 22, 1863 Willis' Battalion numbered 450. By the end of the war it numbered slightly more than 100. The battalion never surrendered.