Charleston Harbor over to the secessionists. South Carolina seceded from the Union on December 20, 1860, after the first election of President Abraham Lincoln. Around this time a Federal garrison from the 1st US Artillery was sent to Fort Moultrie. Unlike the state militia at the other forts, the U.S. Regular Army defenders of Fort Moultrie chose not to surrender to the South Carolina forces. On December 26, 1860, Union Major Robert Anderson moved his garrison from Fort Moultrie to the stronger Fort Sumter. On February 8, 1861, South Carolina joined the five other seceded Deep Southern states to form the Confederate States of America. In April 1861, Confederate troops shelled Fort Sumter into submission, and the American Civil War began. In April 1863, Federal ironclads and shore batteries began a bombardment of Fort Moultrie and the other forts around Charleston harbor. Over the ensuing twenty months, Union bombardment reduced Fort Sumter to a rubble pile and pounded Fort Moultrie below a sand hill, which protected it against further bombardment. The rifled cannon proved its superiority to brickwork fortifications but not to the endurance of the Confederate artillerymen who continued to man Fort Moultrie. In February 1865, as General Sherman marched through South Carolina, the Confederate soldiers finally abandoned the rubble of Fort Moultrie and evacuated the city of Charleston. Postbellum period and 20th century The U.S. Army modernized Fort Moultrie in the 1870s with new weapons and deep concrete bunkers. Weapons of this period included 15-inch and 10-inch Rodman guns (), which were smoothbores, and 8-inch converted rifles, lined down from 10-inch Rodmans. Beginning in 1897, Fort Moultrie's armament was modernized under the large-scale Endicott Program of coast defenses. Eight new reinforced-concrete batteries were completed by 1906, and part of the Second System fort was demolished to make room for batteries Bingham, McCorkle, and Lord. The fort also had a mine casemate to control a naval minefield. In 1901 Coast Artillery units were designated from heavy artillery units, and in 1907 the United States Army Coast Artillery Corps was formed to garrison the new coast defenses. The Endicott Program batteries at Fort Moultrie were: Battery Capron, with sixteen 12-inch mortars, was the largest component of the new defenses. In 1906 it was organizationally split into two batteries, Capron and Butler, each with eight mortars. Batteries Jasper and Thompson provided longer-range weapons with a total of six 10-inch disappearing guns.