On Saturday July 18, 1863 six thousand Union troops, led by the Fifty-Fourth Massachusetts Colored Infantry, frontally assaulted Battery Wagner on Morris Island in Charlestown Harbor and its 1785 Confederate defenders.
The attack was foolhardy; the attackers had to traverse open ground for several hundred yards under enemy fire even before they could reach Wagner. One small angle of the earthwork fort was seized momentarily, but by evening the attack had been successfully repulsed, with massive Federal casualties. Union losses totaled 1515 dead, wounded, or missing compared to only 174 Confederate casualties.
In the face of such losses, the Union military quickly began a siege of Charlestown, featuring heavy batteries, including the huge “Swamp Angel—capable of firing a two hundred pound shot—which would, hopefully, blast Charlestown’s defenses into submission.