Short answers, pulled from the story.
Fort Moultrie is a series of fortifications on Sullivan's Island, South Carolina, built to protect Charleston harbor. The site is now managed by the National Park Service as part of Fort Sumter and Fort Moultrie National Historical Park.
Fort Moultrie was the site of the Battle of Sullivan's Island on the 28th of June, 1776, where William Moultrie and roughly four hundred men repelled a Royal Navy fleet of nine warships. The fort's palmetto log construction, which absorbed cannon fire rather than shattering, inspired South Carolina's nickname 'The Palmetto State' and influenced the design of the state flag.
William Moultrie was the commander of the 2nd South Carolina Regiment who led the defense of Fort Sullivan on the 28th of June, 1776. He designed the blue 'Liberty' flag flown during the battle, and the fort was renamed Fort Moultrie in his honor after the American victory.
Osceola, a Seminole leader, died of malaria at Fort Moultrie in January 1838. He had been captured in late 1837 and transferred to the fort as a prisoner; the Army buried him at the front gate and maintained his grave there.
On the 26th of December, 1860, Union Major Robert Anderson relocated his garrison from Fort Moultrie to the stronger Fort Sumter. Confederate forces later took Fort Moultrie, and Union bombardment beginning in April 1863 eventually pounded the fort below the level of a sand hill. Confederate troops abandoned Fort Moultrie in February 1865 as General Sherman advanced through South Carolina.
The Army lowered Fort Moultrie's flag for the last time on the 15th of August, 1947, ending 171 years of military service. In 1960 the Department of Defense transferred the site to the National Park Service, which operates it as part of Fort Sumter and Fort Moultrie National Historical Park.