A memorial honors slaves who escaped the South for refuge in Alexandria, Va.

The descendants sat in Saturday’s scorching sun, but they dared not complain. Sweat seemed like a minor sacrifice compared with the one made by their ancestors, laid to rest more than 150 years ago around the corner in unmarked graves.

Hundreds had gathered, some coming from as far as California, to dedicate the Contrabands and Freedmen Cemetery in Alexandria. Their journey to find out a little more about their family histories had unexpectedly led them to the city’s history — and a fight to preserve it.

They all had something in common: great-grandparents, great-great-grandparents or other long-lost forebears among the 1,700 African Americans buried here, many after fleeing north to Alexandria during the Civil War to escape slavery. The spot’s significance was buried along with the bodies. Wooden markers had decayed, and the land was covered over by a gas station, office buildings, the Capital Beltway — forgotten by many until the construction of the Woodrow Wilson Bridge.

“I remember playing cowboys and Indians here,” Alexandria Mayor William D. Euille (D) told the crowd. “We had no idea.”

Louise Massoud and Lillie Finklea, both 75, began working together to preserve the cemetery in 1997 after reading a Washington Post article about how an old grave site might affect plans to replace the Woodrow Wilson Bridge.

Kemal Wimbush of Martinsburg, W.Va., holds daughter Moina Maria Wimbush at the memorial’s dedication Saturday. Wimbush is one of many descendants of those buried at the cemetery who attended the event. (Astrid Riecken/For The Washington Post)

They were neighbors who had not previously known each other, but after starting the Friends of Freedmen Cemetery, they were bound together by a 17-year, multimillion-dollar effort to identify bodies, locate descendants and build a towering bronze memorial, which was dedicated Saturday.

During Saturday’s sweltering service, some in the audience fanned themselves to keep cool. Volunteers handed out cups of water. The Washington Revels Jubilee Voices led the audience in old spirituals about praising God and dreaming of freedom.

Oh freedom, oh freedom, oh freedom over me,

And before I’d be a slave I’ll be buried in my grave

And go home to my Lord and be free

More than 20,000 African Americans came to Alexandria with that dream. They were promised emancipation if they got to Union territory and were declared to be “contraband” from the Confederacy. They subsisted in shanties and barracks. Then small pox spread, and hundreds died.

Archaeologists unearthed 540 graves sites at this cemetery. They identified bodies and families, even if only by the name “Child” or “Infant.” A genealogist, Char McCargo Bah, was able to locate 145 families that had ancestors in the cemetery at Church and South Washington streets. Some of them, still living in the area, knew the corner. But only one told Bah of knowing that someone — anyone — was buried there.

The entrance gate leading to the Contrabands and Freedmen Cemetery Memorial in Alexandria was officially dedicated Saturday. (Astrid Riecken/For The Washington Post)

On Saturday, Bah stood beside the mayor. She rang a silver bell as city officials read names of the deceased.

Charlie Alexander. Eliza Alexander.

Gale Brooks Ogden, 47, and her husband, Necholus Ogden Jr., who is 45, stood. A city volunteer handed them a rose. Through her own search of family history, Gale Brooks Ogden had discovered that five generations of her family had lived in Alexandria.

It was through Bah’s genealogy searches that she learned that her great-great-great-grandmother, Martha Alexander, had two children buried at this site. Charlie was 7. Eliza was 22.

“I can almost see them now, walking down the same streets I did, in their period clothes,” said Brooks Ogden, 47, who works in finance. “It empowers me and it fuels me in tough times to understand how far my family has come.”

Infant Baltimore. Maria Baltimore. Martha Baltimore. Moses Baltimore. Thomas Baltimore.

Sherrin Bell Hegamin, a 66-year-old retiree who came from Philadelphia, was an only child and had no children. She discovered that at least a dozen of her family members, including the Baltimores, were buried in the cemetery.

“It’s overwhelming,” Hegamin said. “I never knew there were so many people related to me out there.”

The day before the ceremony, she had noticed a woman who she thought bore some resemblance — the same small frame, a similar stature. She asked for her family name. It turned out that they were distant cousins, and both were planning to attend the service.

Alfred Bolden . . . Infant Nash . . . William Henry Norton.

Fran Burton, 60, grew up in Alexandria and now resides in Sacramento. When she learned that an 8-month-old relative named William Henry had been buried at the site, a revelation struck her.

“William and Henry are the most common names on my side of the family,” Burton said. “And now I’m convinced, completely convinced, that’s because my family wanted to honor the first child in the family born free. So now that name is going to stay in the family.”

The families lined up to visit the cemetery. The processional was led by Massoud and Finklea, the neighbors who had made it all happen. The line snaked around the corner to behold a towering bronze edifice that displayed muscular men and women tangled around thorns and roses. Mario Chiodo said he sculpted to illustrate former slaves enduring periods of struggle, oppression, sacrifice, compassion and hope.

“It’s unbelievable,” Finklea said as she stared at the memorial. “I can’t believe all of these people are here.”

Behind her, hundreds of people milled about the cemetery, discovering family members they had never met, and honoring a history that they once did not know.