Confederate States Army. On 12 April 1861, the first shots were fired at U.S.-held Fort Sumter in Charleston Harbor, South Carolina. This action by the South pushed Meagher into support of the Union cause. He began recruiting men for the Union Army. One of his ads in the New York Daily Tribune read: "One hundred young Irishman—healthy, intelligent and active—wanted at once to form a Company under command of Thomas Francis Meagher." On April 29, his recruits were enlisted as Company K of the 69th Infantry Regiment of the New York State Militia (the "Fighting 69th"). Under the command of Colonel Michael Corcoran, another leading Irish political figure, the 69th fought in the First Battle of Bull Run, a Confederate victory. Corcoran was captured, and Meagher succeeded him as colonel. After Bull Run, Meagher returned to New York to form the Irish Brigade. In lectures, including a famous speech made at the Boston Music Hall in September 1861, he implored the Irish of the North to defend the Union. He was commissioned brigadier general (effective 3 February) to lead the Brigade in the Peninsula Campaign of 1862. At the Battle of Fair Oaks in May, Meagher first led the Brigade in battle. The Union won a defensive victory, and the Irish Brigade furthered their reputation as fierce fighters. This reputation was solidified when the New York printmaker Currier and Ives published a lithograph depicting Meagher on horseback, leading his brigade in a bayonet charge. Following the Battle of Fair Oaks, Meagher was given command of a non-Irish regiment. This experiment was unsuccessful, and thereafter Meagher would command only Irishmen. Meagher's troops fought at the Battle of Gaines' Mill on 27 June. The Irish Brigade arrived in battle after a quick march through the Chickahominy River, as reinforcements for the weakening V Corps. Later, this march and battle were considered by historians as the highlight of Meagher's military career. The Irish Brigade suffered huge losses at the Battle of Antietam that fall. Meagher's brigade led an attack at Antietam on September 17 against the Sunken Road (later referred to as "Bloody Lane") and lost 540 men to heavy volleys before being ordered to withdraw. During the battle, Meagher was injured when he fell off his horse. Some reports said Meagher had been drunk, but Maj. Gen. George B. McClellan's official report noted that Meagher's horse had been shot. Meagher had faced