"P" is for Preservation Society of Charleston. Founded in 1920 as the Society for the Preservation of Old Dwellings, the Preservation Society of Charleston is the oldest community-based historic preservation organization in the country. In 1931 the society was instrumental in persuading the Charleston City Council to pass the nation’s first historic district zoning law. The law established a board of architectural review and designated a 138-acre “Old and Historic District.” The district has since been expanded to include more than 4,800 structures. The adoption of the society’s current name in 1957 reflected the organization’s expanded mission to protect not only dwellings but all sites and structures of historic significance or aesthetic value. The Preservation Society of Charleston has sought to fulfill its mission through programs that focus on preservation education, advocacy, and planning.