High Quality Content by WIKIPEDIA articles! Samuel Sloan (March 7, 1815 – July 19, 1884) was a Philadelphia-based architect and best-selling author of architecture books in the mid-19th century. He specialized in Italianate villas and country houses, churches, and institutional buildings. His most famous building—the octagonal mansion "Longwood" in Natchez, Mississippi—is unfinished; construction was abandoned during the American Civil War.