One hundred and fifty years ago, they were Charleston’s enemy, a new wave of the Union army poised to lay siege to the city.

Upcoming events

July 18: The National Park Service is organizing re-enactors and living history events for 3½ days at Fort Moultrie on Sullivan’s Island. There will be history talks at 10 a.m., noon, 1 p.m. and 2 p.m. on that day, as well as an outdoor concert of Civil War music from 6:30-7:30 p.m.

From 7:45-8:15 p.m., the hour that the 1863 Assault on Battery Wagner began, Lt. Gov. Glenn McConnell will speak, and re-enactors will represent the 54th Massachusetts, the 48th New York and the 7th South Carolina battalions.

In the field in front of Fort Moultrie, 294 luminaries will be lit — one for every Union and Confederate soldier who died in the July 18 battle on Morris Island.

July 19: The city of Charleston will present the movie, “Glory,” whose final scenes depict the July 1863 battle on Morris Island, from 7-9 p.m. at Marion Square.

July 20: The Fort Sumter-Fort Moultrie Historical Trust will present a forum, Toward “A New Birth of Freedom”: Sesquicentennial Reflections on Charleston, the 54th Massachusetts Regiment, and the Battle for Morris Island.

The forum runs from 9 a.m. to 12:30 p.m. at the Dock Street Theatre and is free and open to the public. Speakers include these historians and authors: Joseph T. Glatthaar, Thavolia Glymph, Robert N. Rosen and Stephen R. Wise. College of Charleston history professor Bernard Powers will lead a discussion with the audience.

July 21: The National Park Service’s living history programs will run from 10 a.m. to noon.

At 7 p.m., the city of Charleston will dedicate a monument to the 54th Massachusetts Regiment at White Point Garden on the Battery. The ceremony will include Civil War music, Union and Confederate re-enactors, and remarks by Charleston Mayor Joe Riley.

Also, The Charleston Museum is continuing its Civil War Sesquicentennial observation with its exhibit, “Our Duty was Quite Arduous”: The Union Encampment on Little Folly Island, 1863-1865. It features items the museum’s archaeologists recovered from the beach there after erosion caused by Hurricane Hugo in 1989.

This month, as Charleston observes the sesquicentennial of the July 1863 Civil War fighting at the mouth of its harbor, the soldiers of the 54th Massachusetts are being honored.

At the Battery, near where a prominent statue has stood for decades honoring the Defenders of the Confederacy, the city of Charleston plans to erect a new plaque to the regiment — the first African-American regiment to prove itself in battle.

Dawn Davis, chief of interpretation at National Park Service’s Fort Sumter National Monument, helped plan the four-day-long observance that will begin on July 18.

While it may be overshadowed nationally by the sesquicentennial commemoration in Gettysburg, Pa. — a battle that changed the course of the Civil War — Davis said the 54th’s involvement makes this event in Charleston stand out.

“They’re the first African-American regiment raised in the North. It is their moment to really show that they can fight,” she said.

Their proven ability in battle — about 270 of the 54th’s approximately 600 soldiers were killed, wounded or missing while trying to take Fort Wagner on Morris Island — helped recruit more African-American soldiers.

“This is part of that changing in the war, changing it from saving the Union to a war freeing the slaves,” Davis said.

As with the sesquicentennial of the firing on Fort Sumter two years ago, the Fort Sumter-Fort Moultrie Historical Trust organized the events to strike a somber, educational — not celebratory — tone.

The main event will include a concert and ceremony the evening of July 18 — the night of the Union attack. It will be held on the lawn at Fort Moultrie, the Sullivan’s Island park that offers a view of Morris Island in the distance.

Other events include living history demonstrations, a panel discussion, the marker commemoration and a showing of the movie “Glory” in Marion Square.

That 1989 film, which starred Matthew Broderick and Denzel Washington, brought the history of the 54th Massachusetts to a new generation.

The film helped convince Joseph McGill, a park ranger who now works for the National Trust for Historic Preservation, to become a 54th Massachusetts re-enactor.

McGill since has marched in both of President Barack Obama’s inaugural parades but said this upcoming commemoration will be special.

“We need to shine, just as those men did 150 years ago in proving to the world they could be soldiers,” he said.

McGill said some soldiers of the 54th were captured and imprisoned in Charleston’s jail on Magazine Street, and he and 14 other re-enactors plan to spend the night there on July 19 and 20.

McGill said approximately 200,000 African-Americans served in the Union Army and Navy during the war’s course, but more is understood about the 54 Massachusetts than most.

“They were educated. They left a paper trail,” he said. “Most of the other men were former slaves and did not.”

But the story of the fighting at the entrance to Charleston Harbor goes beyond the 54th Massachusetts, and Davis said the observances will try to tell that larger story, too.

For instance, Clara Barton, a teacher and nurse from Massachusetts who founded the American Red Cross in 1881, played a role.

“A lot of people don’t realize she was on Morris Island as well,” Davis said.

But the most tangible and lasting legacy of this month’s commemoration may be a new bronze plaque at the turn of the High Battery.

The plaque, which won’t be permanently installed until that part of the battery is rebuilt, will describe the history of the Massachusetts’ 54th and its role in the battle, Charleston Mayor Joe Riley said.

“You’ll be able to look at the marker and the map and understand where it was and its military significance,” he said.

It’s also one of the first monuments specifically to African-Americans in that part of the city.

“This is bringing things to the forefront that will increase the understanding of the roles different people played in the Civil War,” said Michael Allen with the National Park Service, which helped plan the event. “That’s not always been the case, but that was then. This is now.”