In response, Major General David E. Twiggs surrendered government property and ordered Federal troops to evacuate Texas.

On April 20, 1861, Colonel Earl Van Dorn mustered the battery into Confederate service with the designation Edgar's Company A, Texas Light Artillery.

Edgar was unable to fully recruit the battery because the soldiers had enlisted for a term of one year, and some men declined to re-enroll.

During this period, Edgar's battery was stationed at Camp Waul,[1] located at Old Gay Hill in Washington County, where it endured a severe measles outbreak.

[1] Brigadier General Henry Eustace McCulloch organized a Texas infantry division at the camp which consisted of four brigades, each with an attached artillery battery.

[4][note 1] On November 24, 1862, the Texas infantry division left Camp Nelson to march to Bayou Meto where it remained until December 13.

[6] Walker's division arrived in Pine Bluff on January 8, 1863, but three days later it began marching toward Arkansas Post to relieve its garrison.

[7] Walker's division returned to Pine Bluff on January 20 where it went into winter quarters, only emerging on April 23 when it marched to Monroe, Louisiana.

[10][note 2] After the affair at Perkins' Landing, Walker's division began marching to Richmond, Louisiana, arriving on June 6, 1863.

Once the Union survivors fell back to the riverbank, the gunboats' fire stopped the Confederates and eventually led Walker to abandon the attack.

Walker ordered Edgar's Battery and the 18th Texas Infantry Regiment led by Colonel D. B. Culbertson to defend a position behind Roundaway Bayou and hold off the Federals while the division's wagon train made its escape.

When the leading Union troops got within 150 yd (137 m), the 18th Texas and the battery opened fire, causing their closest attackers to run away.

The 18th Texas crossed the bayou in pursuit, and when the Union soldiers rallied in a nearby woods, Culbertson ordered his men to return to their original position.

Mower reported that his leading unit, the 5th Minnesota Infantry Regiment came into action and lost 1 man killed and 8 wounded.

[18] In mid-December, the 3rd Brigade, now under Brigadier General William R. Scurry, camped at the Norwood Plantation near Simmesport,[19] guarding the bridge over the Atchafalaya River.

[20] On March 19, Taylor sent the 2nd Louisiana Cavalry Regiment under Colonel William G. Vincent to observe the Union forces at Alexandria.

Early on March 21, Mower led a Federal task force from Alexandria consisting of two infantry brigades, a cavalry regiment, and an artillery battery from Smith's column.

At nightfall, after marching through heavy rain, Mower's force reached Henderson's Hill where Vincent's troops were posted.