The 567-day siege of Charleston during the Civil War was not the first time the Holy City had been invested and shelled.

The British tried to take Charleston by sea in 1776 but were repulsed at the Battle of Sullivan’s Island. Their defeat by Col. William Moultrie and the 2nd South Carolina Regiment gave the state the symbols for its present flag, which was adopted as the state’s “national” flag in 1861 — the crescent moon representing the regiment and the palmetto tree, the spongy tree used to build a fort on the island.

But in 1780 the British finally took the city, the American colonies’ richest, by land. Sir Henry Clinton landed his troops on James Island and cut off the peninsula, and Charleston fell in 42 days. Several thousand Continental troops and local militia surrendered, in the largest U.S. surrender until the fall of Corregidor in World War II.

The Federals in 1863 hadn’t learned from that lesson.

For 567 grueling, murderous, innovative, horrific and inspiring days, they tried, instead, to batter their way past barrier islands and into Charleston Harbor with ironclad warships and rifled cannon, trenches and mines. It was the longest siege of the war and the longest in U.S. military history.

The besiegers failed.

Charleston held, at least until it was abandoned by the Confederates when Gen. William T. Sherman left South Carolina’s Midlands blazing in his wake.

“Charleston was the cradle of secession and (the Federals) wanted to take it just for that,” said historian D.J. Tucker, director of African-American history at Charleston’s Magnolia Plantation & Gardens. “But it became a symbol of futility in combat.”

Charleston endured the siege, but, in the process, became a ruin, the most bombarded city in U.S. history. Its destruction had a profound emotional and political effect on the city and the state.

It cemented Charlestonians’ view of themselves as separate from the rest of the state and the nation and, for their perseverance, somewhat superior.

But, most importantly, the ruined city and its impoverished residents, once rich and powerful, lost their political clout to the Upstate in the seismic shift that occurred after the war. That clout has only recently re-emerged with the elections of Charlestonians Glenn McConnell as president pro tem of the state Senate, Bobby Harrell as speaker of the S.C. House and the now-departed Mark Sanford as governor.

The siege also had a long-lasting effect on American combat.

It saw the ascension of African-Americans as soldiers

It demonstrated that masonry forts were obsolete because of the rifled cannon.

And it saw the advent of a new type of naval warfare, which included the submarine, the torpedo boat and the underwater mine.

The 54th Massachusetts Regiment — made famous in the movie “Glory” for its ill-fated charge on Battery Wagner, outside Charleston Harbor, on July 18, 1863 — was not the first African-American unit to fight in South Carolina during the Civil War. The Union Army’s First S.C. Volunteer Regiment was formed at Port Royal in 1862.

The First S.C. Volunteers, an infantry regiment made up of white Northern officers and freed S.C. slaves, raided behind Confederate lines and, later, as the 33rd U.S. Colored Troops, fought battles in Florida and South Carolina. The federal government would go on to form six other regiments from the state’s freed slaves.

“Their leadership experience was critical because, after the war, a lot of them ended up in leadership positions” during Reconstruction, Joe Long, of the S.C. Confederate Relic Room & Military Museum, said of the First S.C. and the other black units.

Prince Rivers of the First S.C. Volunteers, for instance, represented Edgefield in the state Legislature, starting in 1867, and went on to become a state trial judge and a major general of the state militia. He is buried in Columbia’s Randolph Cemetery, named after Benjamin F. Randolph, a free African-American from Ohio who served on Hilton Head Island in the U.S. 26th Regiment during the Civil War.

But it was the 54th’s charge at Battery Wagner — in which the regiment lost two-thirds of its officers and half of its troops — that led the nation to embrace, however hesitantly, the black soldier.

At the beginning of the war, the idea of arming black men was met “with shock and disgust in the South and a lot of opposition in the North,” said Fritz Hamer, curator of history at the State Museum. “But the Northern soldiers who witnessed (the charge) realized that they could fight.”

“They won their spurs in the eyes of the government,” Long said. “They were lined up, and they were slaughtered. But they showed the world they were combat soldiers.”

The April 1861 fall of Fort Sumter to the slave-defending Confederacy set off a rush by free black men to enlist in the U.S. military. They were turned away, however, because a 1792 law barred African-Americans from bearing arms for the U.S. Army, even though they had fought in the American Revolution.

In Boston, the disappointed men requested that the government change its laws to let them fight, and, in 1862, the casualty-depleted Union did.

By the end of the Civil War, roughly 179,000 black men were soldiers in the U.S. Army, accounting for 10 percent of Union land forces, according to the National Archives. An additional 19,000 were in the Navy. Nearly 40,000 black soldiers died in the war — 30,000 of infection or disease.

By war’s end, 16 African-American soldiers would be awarded the Medal of Honor. There were nearly 80 black commissioned officers. Black women, who could not formally join the Army, nonetheless served as nurses, spies and scouts, the most famous being Harriet Tubman, a scout in the Lowcountry.

From the end of the war through World War I, black soldiers, particularly the Buffalo Soldiers, were seen as among the best fighters in the U.S. Army, the Relic Room’s Long said. But, somehow, between World War I and World War II, the view toward blacks in the military reverted to the pre-Civil War attitude.

Later groups of black soldiers, including the Tuskegee Airmen, were viewed — much as the 54th Massachusetts had been 80 years before — as “experiments” to see, once again, whether African-Americans could and would fight.

“The thread was lost,” Long said. “There was backsliding.”

The rifled cannon, which uses a grooved barrel and a conical shell to increase distance, accuracy, payload and velocity, had been around since the 1600s. But it wasn’t until Union Capt. Quincy A. Gilmore decided to try one against Fort Pulaski outside Savannah that the rifled cannon’s true worth was discovered.

Gilmore, an engineer, thought a bombardment by rifled cannons could punch a hole in the masonry fort and force its surrender, avoiding a lengthy siege.

It worked.

On April 11, 1862, after 30 hours of bombardment, Confederate troops inside Fort Pulaski surrendered to Union forces on Tybee Island.

The rifled cannon had rendered masonry forts obsolete.

And so it was in Charleston Harbor when Gilmore, now a brigadier general, hauled his rifled cannons onto Morris Island.

Using an array of the cannons — one of the largest being the “Swamp Angel,” which was capable of hurling shells into Charleston itself — Gilmore pounded the multi-story Fort Sumter into a heap of rubble. But instead of causing Sumter’s surrender, the piles of rubble, reinforced by cotton bales soaked in sea water, made the fort even stronger.

“The biggest danger in the fort was flying brick fragments,” Long said.

Fort Moultrie was reinforced with sand, cotton bales and Sullivan’s Island’s famed palmetto trees, using the fort’s walls only as a frame on which to build.

Both survived naval and land bombardment. Sumter’s defenders also fought off a direct, amphibious assault. It wasn’t until Sherman blazed his way through Columbia and the Midlands in February 1865 that Charleston and its famous forts were abandoned by the Confederacy.

But never again would forts be made from brick.

While Gilmore was hammering away at Charleston’s defenses from Morris Island, his naval counterparts, Rear Adm. Samuel Du Pont and, later, Rear Adm. John Dahlgren were finding Charleston Harbor almost impenetrable.

The first Union attack into the harbor — on April 7, 1863 — “is the biggest battle that no one has ever heard of,” Long said.

Du Pont, commanding a fleet of nine ironclad warships, was ordered to attack, even though he did not expect to succeed.

He had taken Port Royal by reducing its two forts, but they were inferior compared to the fortifications around Charleston Harbor.

In all, the Confederates had 72 cannon ringing the harbor.

Du Pont had 32.

Those 32 guns were mounted on the ironclad New Ironsides, one of the world’s most powerful warships, and seven monitors, new armored ships that some said resembled floating hatboxes.

While the ironclads were new technology themselves — an American invention introduced in Virginia on March 9, 1862, when the USS Monitor and CSS Virginia, also called the Merrimack, fought to a draw in Hampton Roads — Charleston’s Confederate defenders used an array of weapons to defend against them.

They strung booms across the ship channel between Fort Sumter and Fort Moultrie and placed new-fangled underwater mines, which they called torpedoes, along the boom. If a ship penetrated this outer line of defenses, it still would have to confront secondary defenses, consisting of artillery batteries on Castle Pinckney, Fort Ripley and James islands. Should a ship be fortunate enough to survive that gantlet, it would have to endure the shelling of gun emplacements in White Point Gardens, today known as The Battery.

In Du Pont’s April 1863 attack, the lead ship, the Weehawken, struck one the new mines and was disabled. A ship that went to her aid, the Passaic, then was struck by cannon fire 35 times in 35 minutes and crippled.

And on it went.

In all, Confederates fired 2,209 shots and registered 520 hits.

The Union monitor Keokuk sank off Morris Island — marking the only time during the Civil War that an ironclad was sunk by cannon fire. Its two 11-inch guns were retrieved by the Confederates and turned on their former owners. Today, one of the cannons is displayed on The Battery.

After that drubbing, the U.S. Navy had had enough and settled in for a blockade that would last until the end of the war.

One of the most enduring episodes of that blockade is the story of the CSS Hunley, which became the first submarine to sink a warship in combat, only to herself sink and be recovered 136 years later, on Aug. 8, 2000.

The raising of the Hunley, and the pomp and ceremony that surrounded the reburial of its crew, was noted around the world

The interest sprang “from the idea that this innovative weapon, that no one had tried before, had actually sunk a ship,” the State Museum’s Hamer said. “But, strategically, it didn’t do a darn thing (to end the blockade). But these eight men had the guts to use this novel weapon and managed to succeed.”

Today, submarines play a major role in the U.S. arsenal.

Perhaps the most lasting legacy of the siege of Charleston was the political shift it hastened.

At the end of the war, Charleston was in ruins, not just from the shelling but also because of a fire that wrecked the city in December 1861.

South Carolina’s rich aristocracy was rich no more — not just in Charleston, but throughout the Lowcountry and the Midlands.

Their slaves were gone. Their plantations lay fallow. Their homes were destroyed. And, in many cases, South Carolina’s white men were killed or maimed.

White South Carolina, long politically and economically centered on Charleston, lost its political power during Reconstruction — when blacks received the vote and elected the state’s first African-American state representatives, state senators and congressmen.

The white aristocracy briefly reclaimed power when Columbia’s Wade Hampton — a former Confederate cavalry general and formerly one of the richest men in the United States — and his Red Shirt supporters wrested back the governorship.

But Hampton lost the 1890 governor’s race to populist, racist “Pitchfork” Ben Tillman of Edgefield County, signaling the rise of Upstate economic and political power.

“Tillman didn’t like the Charlestonians,” Hamer said. “He thought they were dandies.”

Despite their losses, members of the Charleston aristocracy remained proud and unreconstructed. They were mostly English and Huguenot. The rest of the state was mostly German and Scots-Irish.

“Charleston has always been a different socio-economic center from the rest of the state,” Hamer said. “They worship their ancestors. It’s the blue-blood mentality.”

The rest of the state had sent its boys off to the Civil War. But the war had pounded Charleston for four years.

“Charleston was on the front lines the whole time,” Long said. “They were the nut the Federals couldn’t crack. And, as a result, the Charleston identity would become more intense through the experience of the siege.”

Charleston would remain poor and proud until World War II, when the establishment of the Charleston Navy Yard revived its economy, Hamer said. Since then, the inclusion of African-Americans in its governance, the influx of tourists from around the world and the resurgence of its downtown after Hurricane Hugo also have changed the city, he said.

But the aristocratic core remains.

“The Charleston civilians were within the sound of the guns, and the rest of the state was not,” Long said.

“That made all the difference.”