From the three-story Franklin and Armfield Office building in Alexandria, one of the largest slave trades in the South was operated. The Franklin and Armfield partnership was established in 1828 and continued until 1836. At its peak, the firm had agents in almost every southern city, owned a fleet of ships, and trafficked in thousands of enslaved African Americans annually. The building was erected ca. 1812 as a residence for Robert Young, a brigadier general in the District of Columbia militia. While it was occupied by Franklin and Armfield, slave pens were built in the yard. The building served the slave trade until the Civil War when it was converted to a Union prison. The slave pens were removed for new houses in the 1870s after the property was acquired by Thomas Swann, who added the mansard roof. Since renovated for offices, the Franklin and Armfield Office building displays little hint of its notorious past.