In the early nineteenth century, as the city grew steadily from the Delaware River to the Schuylkill River, it became obvious that Rittenhouse Square would become a highly desirable address. James Harper, a merchant and brick manufacturer who had recently retired from the United States Congress, was the first person to build on the square, buying most of the north frontage, erecting a stately townhouse for himself at 1811 Walnut Street (c. 1840). Having thus set the patrician residential tone that would subsequently define the Square, he divided the rest of the land into generously proportioned building lots and sold them. Sold after the congressman's death, the Harper house became the home of the exclusive Rittenhouse Club, which added the present facade in c. 1901.