His attention soon turned to Texas' struggle against Mexico. Henderson began making speeches to raise money and an army to go to the aid of the Texas cause. Henderson and several volunteers traveled to Texas hoping to participate in the fight for independence. By the time the group arrived in June 1836, many of the major events had already taken place. The Texas Declaration of Independence had already been signed on March 2, and David G. Burnet was elected interim President of the new Republic of Texas on March 10. The Alamo had fallen on March 6, and Sam Houston had been victorious on April 21 at the Battle of San Jacinto. On May 14, 1836, Antonio López de Santa Anna has signed the Treaties of Velasco agreeing to withdraw his troops from Texas. Interim President Burnet commissioned Henderson as a brigadier general in the Texas Army, with orders to return to North Carolina to raise troops to serve in Texas. This Henderson did at his own expense.