By the time the cigar-box sized plaster-covered container was pried out of the Massachusetts Statehouse cornerstone, it was getting dark outside.

Museum of Fine Arts preservationist Pamela Hatchfield had worked all day on Thursday, chipping and sawing away at the stone surrounding the 219-year-old treasure. Record show it was likely buried by two of the country’s most well-known historical figures, Paul Revere and then-Massachusetts governor (now beer) Sam Adams.

It was discovered during a water leak investigation at the historic building this week. And it may be the country’s oldest unopened time capsule, according to ABC News. 

Hatchfield, bundled up in a coat and warmed by a space heater, worked lying on her back with the large cornerstone, propped up by blocks of wood, hovering above her.

She didn’t want to risk turning the block upside down and disrupting the contents of the box. As she worked, small silver coins fell to the ground. 

After more than seven hours of labor, it was finally finished, and Hatchfield emerged with the green-tinted box smiling to a round of applause.

“I feel happy and relieved. And excited. And really interested to see what’s in this box,” Hatchfield said according to the Boston Globe.

The time capsule is believed to have been buried in 1795, and was unearthed one other time in 1855 during a renovation project, according to the Boston Herald. 

According to the Boston Globe, it was an “emergency renovation.” Silver coins were thrown in for “good luck” then; it is unclear what else might have been added or removed.

Its contents might also include Massachusetts Colony Records, newspapers, and an engraved silver plate, some items dating back to 1652, the Herald reported.

Water damage in that part of the building initially prompted crews to work in that area, which could be a sign of trouble for its contents.

“The cause of this whole effort is that there’s been a substantial water problem now for about 30 years in this corner, so there’s been additional deterioration,” said Massachusetts Secretary of State Bill Galvin, who has overseen the project along with MFA. “We know that in 1855 when it was restored that it was a very humid day.”

“We also have some notes that indicate they washed some of those contents in acid, which is of course a concern. So we don’t know how much has deteriorated over time,” he added, according to CBS Boston. 

In October, a 113-year old time capsule was removed from inside the lion statue in the Old State House building blocks away. It was inspected then eventually returned to its home.

The museum will perform an X-ray of the contents of this latest box of history. And according to ABC News, the public will have an opportunity to view its contents on display. This box is likely to also be placed back in its home, Galvin said.

“It will be opened probably sometime next week,” said Galvin according to the Globe. “Ultimately it will be put back in the box and ultimately back in the stone.”