Just months after experts discovered a work from a Jacob Lawrence series that currently forms the basis of a traveling survey, curators have authenticated another painting from that body of work that was long thought to be missing.

Panel 28 of Lawrence’s 30-work painting series “Struggle: From the History of the American People” has been located in the holdings of a resident in New York’s Upper West Side, the New York Times reports. The work’s owner, a nurse in her late 40s, said she discovered that she may have a Lawrence on her hands after her son told her about the Metropolitan Museum of Art’s version of the show. She then brought the work to the attention of curators at the Met, who visited her home and authenticated it.

The painting is titled Immigrants admitted from all countries: 1820-1840—115,773, and it depicts three pared-down figures clustered together against a brown background. Just three works from the series are still missing. The Peabody-Essex Museum in Salem, Massachusetts, which organized the traveling show, is seeking tips on their whereabouts.

[How Jacob Lawrence used painting to tell the stories of Black Americans.]

Lawrence’s “Struggle” series, painted between 1954 and 1956, focuses on “the struggles of a people to create a nation and their attempt to build a democracy,” as the artist once put it. It includes images depicting events that took place in the U.S. between 1775 and 1817, with their subjects including a Patrick Henry speech on slavery, westward expansion, and Shays’ Rebellion, an armed citizen’s rebellion over a monetary crisis that formed the basis of the recently discovered 16th panel.

The work’s current owner told the Times that she does not know how her mother-in-law, who gave her the work, came to own it, and she was not previously aware that it was of art historical significance. “I didn’t know I had a masterpiece,” she said. The 28th panel will now head to the Seattle Art Museum in Washington, which will open its version of the “Struggle” show on March 5.