The Peninsula Campaign (also known as the Peninsular Campaign) of the American Civil War was a major Union operation launched in southeastern Virginia from March through July 1862, the first large-scale offensive in the Eastern Theater. The operation, commanded by Maj. Gen. George B. McClellan, was an amphibious turning movement against the Confederate States Army in Northern Virginia, intended to capture the Confederate capital of Richmond. McClellan was initially successful against the equally cautious General Joseph E. Johnston, but the emergence of the aggressive General Robert E. Lee turned the subsequent Seven Days Battles into a humiliating Union defeat.