In the early 1840s, where the steps of the Library of Congress now stand, a group of American abolitionists gathered in a modest boardinghouse to plot the destruction of slavery.

The house belonged to a relatively obscure Washingtonian, a widow named Ann Sprigg. In those days, boardinghouses like Sprigg’s were fixtures of the capital landscape—where congressmen, senators, government officials, and the like tended to live during legislative sessions. Quarters were often cramped. Men rented a room—or just a bed, or even half of a bed—and communed in shared bathrooms and living spaces, with the day’s debates sometimes carrying over to the dinner table. Many houses developed reputations as being favored by certain factions, turning them into political clubs as much as living quarters.

In 1841, Ann Sprigg’s house came to be known as the “abolition house.” Three anti-slavery Whig congressmen—Seth M. Gates, a New Yorker, William Slade, a Vermonter, and Joshua Giddings, an Ohioan—moved in alongside two prominent abolitionists, Theodore Dwight Weld and Joshua Leavitt. Leavitt—a New Yorker from a landowning family who shared a Sprigg House bed with Weld—quickly set about convincing the representatives to work alongside the wider abolition movement as an anti-slavery lobby. The group became the brain trust behind the first significant congressional campaign to combat slavery from the nation’s capital.

The brain trust’s goal was straightforward: to develop a caucus within the legislature, a lobby to influence the legislature, or at the very least an argument that would challenge the power of slavery and slaveholders in the American government. But it was also radical, representing a major sea change in American history, and ultimately a turning point in slavery’s demise. Up until this point, the anti-slavery movement had largely eschewed politics. Led by William Lloyd Garrison and his followers, the early abolitionists focused strictly on changing hearts and minds—what they called “moralsuasion”—not changing votes. Garrison once even burned copies of the U.S. Constitution (which he called “a Covenant with Death and an Agreement with Hell!”) on stage—a flaming, charred reflection of the fact that he preferred challenging slaveholder power from outside the halls of power.

By the time the brain trust moved into the Sprigg House, however, the movement had started to splinter, with more abolitionists taking up the banner of political activism. A year prior, one group of abolitionists broke with Garrison by forming their own political party. Known as the Liberty Party, it was the first ever expressly anti-slavery party in American history, though it never registered more than a blip on the national political radar. As a result, many anti-slavery Whigs like Giddings and Slade opted to remain Whigs, where they could challenge slavery within the existing two-party structure.

This shift within the anti-slavery movement was partly a result of recognizing that as of the late 1830s and early 1840s, slavery’s defenders clearly had the upper hand, especially in the United States Congress. In fact, so great was slaveholder influence in the nation’s capital that in 1836 the U.S. House of Representatives passed a series of resolutions that became known as the “Gag Rule.” At the time, constituents would send petitions to their legislators to read on the house floor; the Gag Rule barred the reading of the many anti-slavery petitions congressmen received, which left slavery virtually unchallenged in Congress.

Carroll Row, which included Ann Spriggs’ boarding house, was located at the site of present-day Library of Congress. Courtesy of Library of Congress.

The first task of the boarders in the Sprigg House was to repeal the Gag Rule. Weld and Leavitt helped prepare anti-slavery speeches and advised the congressmen on strategy, forming what Giddings described as an informal “select committee.” They soon found a key ally in president-turned-congressman John Quincy Adams. Though Adams never lived in the Sprigg House, he spent hours there conferring with the boarders. Finally, on December 3, 1844, thanks in no small part to plans hatched at the Sprigg House, Congress repealed the Gag Rule, galvanizing anti-slavery politicians across the country. Many of them later became “Conscience Whigs,” a faction within the Whig Party that opposed slavery, in opposition to their rivals, the pro-slavery “Cotton Whigs.”

While not as radical as many of his “Conscience Whig” colleagues Abraham Lincoln was himself an anti-slavery Whig, and this is perhaps what drew him to the Sprigg House when he moved to Washington, D.C. in 1847 as a little-known congressman from Illinois. For the next two years, it was where he slept, ate, and debated his fellow boarders on the major political topics of the day, including the Mexican-American War, the annexation of Texas, and the possible expansion of slavery into the West. Though the other members of the brain trust had moved on by then, Lincoln’s fellow Midwesterner in the House, Giddings, still lodged there, and the two most certainly dined together when in session.

Lincoln spent only a single term in Congress, but his time at the Sprigg House was clearly a formative experience, if not also a fond memory for him. When he returned to Washington more than a decade later, this time as president of a fractured nation, he looked in on Ann Sprigg, who had since moved houses and fallen on hard times. When Lincoln learned that she needed help, he got this “most estimable widow lady” a job working as a clerk in the Treasury Department, a position that allowed her to support her family through the war.

Ann Sprigg died in 1870, and her boardinghouse—and the entire block of row houses on which it stood—was demolished in 1887 to build the Library of Congress. Since then, the story of this old D.C. boarding house and the woman who ran it has been largely forgotten. The history of the anti-slavery movement has often focused on bigger, more prominent figures and emphasized the work of activists based in New England or New York and not necessarily a slaveholding city like Washington, D.C.

Yet for the better part of a decade, Ann Sprigg’s abolition house formed the nucleus of a new political attack against slavery. It was there at the dining room table that anti-slavery politicos put together a strategy for combatting slavery within the halls of Congress, a change that thrust anti-slavery activism away from the fringe and placed it right in the heart of American politics.

Editor’s note: This piece has been updated to reflect that while Joshua Leavitt came from a wealthy family, he was not personally wealthy.