As a matter of course, the young Lewis entered West Point in 1836. Here, however, his career was cut short. He became involved in a personal conflict with Jubal A. Early, who had insulted him on the parade ground, and cracking that worthy's head with a mess-hall plate, as the story runs, was retired from West Point; but in 1839 entered the regular army as lieutenant in the Sixth Regiment of Infantry, and fought against the Seminoles under Zachary Taylor and under his own father. During the war with Mexico he did splendid service. He led the storming party at Chapultepec, and was brevetted Captain and then Major for gallantry displayed at Contreras, and Cherubusco, and Molino Del Rey. That war being ended, he served for fourteen years on the frontier, and in 1859 marched against the hostile Indians and defeated them.
On the secession of Virginia he promptly resigned his command in the old army, tramped on foot across the plains to Austin, Texas, came straight to Richmond, and in April, 1861, was made Colonel of the Fifty-seventh Virginia, and twelve months afterwards, in April, 1862, was commissioned Brigadier-General. In that capacity he fought at Seven Pines, at Malvern Hill, at Second Manassas, at Sharpsburg, displaying everywhere conspicuous gallantry, and winning by his coolness under fire, by his stern perseverance and his indomitable pluck, the applause of his superiors and .the entire confidence of his men.
During the first Maryland campaign he was made Provost Marshal of the army, and received the personal thanks of General Lee for the ability with which he discharged the duties of that office.
In September, 1862, his brigade, which comprised the Fifty-seventh, Fifty-third, the Fourteenth, the Ninth and the Thirty-eighth Virginia, was incorporated with Pickett's Division.
General Armistead was no "holiday soldier," no "carpet-knight." "He was," says Col. Martin, "a strict disciplinarian, but never a martinet. Obedience to duty he regarded as the first qualification of a soldier. For straggling on the march or neglect of duty on the part of his men, he held the officer in immediate command strictly responsible. The private must answer to the officer, but the officer to him."
