In the Texas War for Independence, Reuben R. Brown joined the Matamoros expedition in January 1836. While serving in a detachment that captured the horses of Gen. Urrea of the Mexican army, Brown was taken captive in a counterattack and spent 11 months in prison in Mexico before finally escaping. In his old age, he lived at Sur Mer, the home of his daughter Mrs. James Perry Bryan, a great-granddaughter by marriage of Moses Austin, whose courage had led to the colonization of Texas.