In 1855 , he was promoted to first lieutenant .
In 1855 , he was assigned to the newly organized 2nd U.S. Cavalry , a regiment under Col. Albert Sidney Johnston that also included Robert E. Lee and numerous other future Civil War generals .
In 1855 , he was promoted to first lieutenant and assigned to the newly organized 2nd U.S. Cavalry , a regiment under Col. Albert Sidney Johnston that also included Robert E. Lee and numerous other future Civil War generals .