James and Lucretia Mott created the Pennsylvania Anti-Slavery Society in 1833 in Philadelphia, Pennsylvania. In 1838, the Pennsylvania Anti-Slavery Society built Pennsylvania Hall. Pro-slavery rioters burned the building three days after it opened. Several prominent abolitionists such as Mary Grew, James Miller McKim, and Robert Purvis served as members of the society. While working at the society, William Still, helped a man named Peter Freedman, who he later discovered was his own brother.