When was Grumpblethorpe (at 5267 Germantown Avenue) built?
It was built in 1744 by John Wister, an immigrant from Germany in 1727 who had made money as a wine merchant. It was built of Wissahickon Schist which is dressed in front, but left as rubble on the sides and rear. Source: Philadelphia Architecture: A Guide to the City, 1994, p.25, John Andrew Gallery, 720.