a regiment, but Greene chose to serve New York. The officers of the 60th were dismayed when the elderly, gray-haired man reported for duty. They had requested that their lieutenant colonel be promoted, which would have raised many of them in rank themselves. On April 28, 1862, Greene was appointed brigadier general of volunteers and served on the staff of Maj. Gen. Nathaniel Banks in the Shenandoah Valley campaign against Stonewall Jackson. At age 61, Greene was one of the oldest generals in the Union army and his troops took to calling him "Old Man" or "Pap" Greene. (There were actually 17 general officers in the Civil War older than Greene.) However, his age did not keep him from being one of the most aggressive commanders in the army. He commanded the 3rd Brigade, 2nd Division, II Corps, of the Army of Virginia at the Battle of Cedar Mountain during the Northern Virginia Campaign. Attacked by a Confederate force three times the size of his own, Greene and his men refused to give ground, holding out until the neighboring Union units were forced to withdraw. His division commander, Brig. Gen. John W. Geary, received a severe wound during the action and Greene took command of the division temporarily. Greene was again temporarily elevated to command of his division, now designated part of the XII Corps of the Army of the Potomac, at the Battle of Antietam. His division's three brigades were led by junior officers who had survived Cedar Mountain. Even though XII Corps commander Brig. Gen. Joseph K. Mansfield was killed shortly after the fighting began, Greene led a crushing attack against the Confederates near the Dunker Church, achieving the farthest penetration of Maj. Gen. Stonewall Jackson's lines of any Union unit. Under immense pressure, Greene held his small division (only 1,727 men engaged at the start of the day) in advance of the rest of the army for four hours, but eventually withdrew after suffering heavy losses. While the division was posted to Harpers Ferry, Greene took a three-week sick leave. Maj. Gen. Oliver O. Howard speculated that Greene, like many of his fellow officers, was sickened by the stench of dead and wounded at Antietam. When he returned, there was a new division commander, Brig. Gen. Geary. Greene was disgruntled that Geary, with only a few days seniority over him, was selected for the post; Geary had