The news of the attack on Fort Sumter reached Washington, D.C. on April 14, 1861. President Abraham Lincoln called for 75,000 militiamen to serve for 90 days. These men were needed to put down the rebellion of the Southern states. In meetings across the North people cheered the flag and called those who seceded "traitors"! Across the North, eager volunteers responded to calls from local governmental officials to join newly raised state regiments. Governor Andrew Curtin of Pennsylvania issued a proclamation asking for 13,000 able-bodied Pennsylvania men to volunteer to help preserve the Union. Within three days, thousands of men had come to Harrisburg to enlist. But they had no place to organize or drill. Governor Curtin decided to use the County Agricultural Society in Harrisburg. Major Joseph F. Knipe officially opened the camp on April 18, 1861, and named it Camp Curtin in honor of the governor (the planned name had been Camp Union). By the end of April, it had sent 25 regiments into the field. From December 1861 to March 1862, the camp was commanded by Major Truman Seymour. In June and July of 1863, General Robert E. Lee invaded Pennsylvania for a second time. His target was Harrisburg and Camp Curtin. However, before he could get there, an accidental meeting between Confederate and Union troops started the Battle of Gettysburg. After the battle Lee's army retreated back to Virginia.