WALTHAM, Mass. (AP) – The little that Kathryn Peirce knew growing up about her mother’s twin was that the baby died at birth and was probably a boy. After years of research, her cousin uncovered a birth certificate that revealed the baby was actually a girl, and was buried at St. Joseph cemetery in Boston in 1923. But Peirce couldn’t find a cemetery with that name in Boston, and her questions remained.

The family mystery was solved earlier the year when archeologists discovered a forgotten burial site on the grounds of St. Joseph church in the Roxbury section of Boston. On Saturday, Peirce’s aunt was honored with 1,200 others in a ceremony led by officials from the Boston Archdiocese. Bishop Walter J. Edyvean and The Rev. Walter Waldron, former pastor at St. Joseph, led more than 60 people who gathered at Calvary Cemetery in Waltham to dedicate the new, final resting place for the bodies forgotten for decades.

“We don’t think the baby had a ceremony or a blessing, so this was nice,” said Peirce, of Natick.

St. Joseph church was built in 1845 and the cemetery established soon after. By 1868 it had filled, mostly with young families of Irish immigrants who presumably fled their home country at the beginning of the Potato Famine.

By 1882, according to the archdiocese, the cemetery had been wiped from city maps and tombstones had disappeared.

Earlier this year, the church property was sold to the Roxbury Charter High School. During preliminary surveys, an archaeological team found a human bone.

The team, as well as members of the church, had wrongly believed that bodies from the cemetery that had once been there were exhumed and re-interred someplace else, according to Kirk VanDyke, one of the field archeologists.

“I don’t think that anyone expected so many people,” he said.

Discovering so many remains in such a small place was not easy, VanDyke said at Saturday’s ceremony.

“It’s hard to do this kind of work. You have to assume what you’re doing is right,” he said. “Every scoop full of dirt, we hoped it would be that last.”

When the work was finished, the team had recovered the remains of 1,238 people.

There was no map of the Roxbury grave site, according to Robert Visconti, the executive director of The Catholic Cemetery Association of the Archdiocese of Boston. So the bodies – which were sometimes buried densely with family members – were exhumed one grave shaft at a time. They were then put together in containers and recently re-interred at the Calvary Cemetery.

A statue of St. Joseph stands in a flower bed at the center of the new plot atop a podium that was found at the excavation site among the rubble of broken headstones.

A plaque is attached with an Irish phrase that would have been common on a mid-19th century tombstone: “Ar dheis dia go raibh a n-anam,” which means “to the right of god their souls will sit.”

After learning about the burial site at St. Joseph, Peirce and her family decided to give her aunt a “good, Irish name”: Francis Therese Wrenn.

Peirce said her mother, who was buried at a Calvary Cemetery in nearby Woburn, would be happy her sister received a better burial.

“It’s just ironic, they’re both at Calvary,” Peirce said. “It’s like the twins are in the same cemetery.”