A modest brick rowhouse in the middle of downtown Brooklyn that once protected runaway slaves is the city’s newest historic landmark.

The Harriet and Thomas Truesdell House at 227 Duffield Street was designated an individual landmark by the Landmarks Preservation Commission Tuesday, after years of grassroots efforts to protect the Greek-Revival style former row house, said to be a rare surviving example of a 19th-century abolitionists’ home.

“When we talk about 227 Duffield Street we’re not just talking about a building, we’re talking about a deeper history, and something we cannot afford to lose because it’s part of our heart and soul,” said Mayor Bill de Blasio during a ceremony at City Hall Tuesday. “It was the home of the noted abolitionist Harriet and Thomas Truesdell. It was a refuge for those fleeing slavery. And remember that for so long in this country, fleeing slavery was not treated as a heroic act, but was treated as an act of illegality. So, the Underground Railroad, even here in New York City, was needed to protect people from unjust laws across our nation.”

The Truesdells were prominent abolitionists at a time when the economy of New York City, and especially Brooklyn, was underpinned by southern slavery. They lived in the house from 1851 until 1863, “a time marked by more clandestine abolitionist activity due to the harsh penalties on those who broke the 1850 Fugitive Slave Law, which required that all escaped slaves be returned and that officials and citizens of free states had to cooperate,” according to de Blasio’s office.

“The property remained in the Truesdell family until 1921. While a two-story commercial extension was added in 1933, the house retains its 19th-century form and historic fabric above it, and its significant association with the Truesdells and the history of the abolition movement in Brooklyn prior to the Civil War is still legible,” de Blasio’s office said.

“The Truesdells were active abolitionists during a decisive period of resistance and their legacy of commitment is representative of the many abolitionists who supported total emancipation as part of the local and national movement,” said Landmarks Preservation Commission Chair Sarah Carroll in a release.

But the effort to landmark the house has languished for more than 16 years -- in part because of an absence of historical records officially documenting its use as an Underground Railroad location -- and at times the property came perilously close to demolition.

Raul Rothblatt, an activist and member of Save 227 Duffield, told Gothamist last year he first lobbied the Landmarks Commission to protect the house in 2007 when the Bloomberg administration first considered seizing the property by eminent domain to create a park. The proposal was ultimately abandoned after expert testimony about its origins and public outcry.

The property's most recent owners, Brownstoner reported, have been listed on DOB documents as "developers and partners" Samiel Hanasab and Yuval Golan. "In 2019, the owners of 227 Duffield Street filed plans to demolish the historic house and put up a 13-story mixed-use building in its place," according to Brownstoner, and an eviction notice was served on the property.

An attempt to reach Hanasab and Golan Tuesday afternoon was not successful, though Hanasab's lawyer Garfield Heslop told Brooklyn Paper, "from a financial perspective this is devastating for my client. Nonetheless we accept the Commission’s decision, and we’ll see what happens.”

It's not clear if anyone is currently residing at the site -- court papers from October say the property was abandoned with broken windows.

In addition to Downtown Brooklyn being a hotbed for activism, the existence of an underground tunnel beneath the home further strengthened people's beliefs that 227 Duffield was once a stop on the Underground Railroad. Nearby Plymouth Church is home to one of the stops on the Underground Railroad, which remains intact today.

But the city was uninterested, Rothblatt said. After the controversy over eminent domain, the Bloomberg administration committed $2 million to honor abolitionist history in the neighborhood, including renaming Duffield Street as Abolitionist Place, but took no further steps to preserve the house or highlight its legacy. One prominent supporter, Joy “Mama Joy” Chatel, whose family lived in the house at one point and fought for permanent recognition, died in 2014 without ever seeing the house landmarked.

“Saving this house is a testament to the struggle that my mom led,” said Shawné Lee, Chatel’s daughter and a founding member of Friends of Abolitionist Place, in a release Tuesday. “Mom always wanted the building to become a community-controlled cultural center where Black people can celebrate our history and culture. Today we are one step closer to that dream, and we hope that today’s events open the floodgates for the recognition of other Black landmarks.”

The next step, preservationists hope, is to turn the building into the Heritage Center at 227 Abolitionist Place where visitors can learn about the local abolitionist movement via interactive learning experiences and artist residencies, according to Friends of Abolitionist Place.