In 1776, during the American Revolutionary War, the British army occupied New York and much of New Jersey. In 1777, the army moved to take Philadelphia, the capital and principal city of the Thirteen Colonies. With the city threatened, many Philadelphians fled. Daniel Wister's family of seven fled to the North Wales, Pennsylvania (Gwynedd Township), home of Hannah Foulke, a widow whose son had married a sister of Lowery Wister and whom Sally knew as "Aunt Hanna[h]" The main house is located a few hundred meters east of Wissahickon Creek, where the Penllyn station has been built; the Foulkes' mill stood nearby. The Wisters probably arrived about late 1776; they were certainly there by early 1777. Sally kept up correspondence with at least Debby Norris and a few others.