and the Battle of Resaca de la Palma, Texas, in 1846. He was promoted to first lieutenant on September 30, 1849. He served as regimental adjutant from July 1, 1854, to March 3, 1855. Pleasonton was promoted to captain on March 3, 1855. Civil War Peninsula to Chancellorsville At the start of the Civil War in 1861, Captain Pleasonton traveled with the 2nd Dragoons from Fort Crittenden, Utah Territory, to Washington D.C. Despite active politicking on his part, attempting to capitalize on the faded political connections of his father (who had died in 1855), Pleasonton did not earn the rapid promotions of some of his colleagues. He was transferred to the 2nd U.S. Cavalry Regiment on August 3, 1861. He was promoted to major on February 15, 1862. He fought without incident or prominence in the Peninsula campaign, providing Army of the Potomac commander Major General George McClellan with little accurate or valuable information. On May 1, 1862, Pleasonton was nominated by President Abraham Lincoln for promotion to the grade of brigadier general of volunteers to rank from July 16, 1862, and the United States Senate confirmed the appointment on July 16, 1862. President Lincoln formally appointed Pleasonton to the grade on July 18, 1862. He then commanded a brigade of cavalry in the Army of the Potomac. On September 2, 1862, Pleasonton assumed division command in the cavalry of the Army of the Potomac. As McClellan's chief cavalryman, it was part of Pleasonton's duties to provide his commanding general with intelligence, especially the size of enemy formation. In general, McClellan relied on the erroneous information provided to him by private detective Allan Pinkerton, which resulted in McClellan's idee fixe that he was constantly unnumbered by the Confederate forces he faced. During the Maryland campaign of 1862, Pinkerton had no agents in place, so the task of estimating enemy strength fell to Pleasonton, who turned out to be as inept at it as Pinkerton. As a result, McClellan remained convinced that Confederate General Robert E. Lee's forces outnumbered his two-to-one, when the truth was almost exactly the opposite. He was wounded in the right ear by the concussion of an artillery shell at the Battle of Antietam on September 17. Ever ambitious, Pleasonton was displeased that he was not promoted to major general of volunteers for his actions, claiming erroneously that his division, and particularly the horse artillery assigned to