on august 2 under the direction of colonel edward w. serrell union engineers began constructing a battery further inland with the intention of bombing the city of charleston directly. by august 17 the massive battery was ready for its armament. lieutenant charles sellmer with a detachment of the 11th maine infantry was called in to man the 200-pound parrott rifle now being referred to as the "swamp angel". on august 21 gilmore sent an ultimatum to beauregard to abandon forts wagner and sumter or charleston would be fired upon. when gilmore received no reply by the following day the first shot was fired from the swamp angel into charleston using the steeple of st. michael's church for a bearing. on august 22 confederate batteries tried in vain to silence the swamp angel. beauregard scorned gilmore for turning his guns on a civilian city and demanded an opportunity to evacuate to citizens. gilmore complied with a day of cease-fire but also took the opportunity to express the fact that charleston was a legitimate military target as an ammunition supply. the firing resumed but on the 36th shot the swamp angel burst and was not replaced during the campaign. it was the first time a civilian population was deliberately targeted for military purposes during the civil war.