There is probably no square mile in America that has taken custody of paper more seriously. The Johnson House kept accounts while sheltering people escaping slavery. Wyck holds the letters and ledgers of nine generations of one family. Stenton, Cliveden and Grumblethorpe have survived war, fire, and three centuries of ordinary neglect because somebody in every generation decided the record mattered enough to look after properly.

Which makes Germantown a strange place to hand your only copy of something important to an address that turns out to be a mailbox.

Although highly concentrated in Old City, Rittenhouse Square and Center City – we see the modern version of that custody problem constantly from this part of Philadelphia near Manayunk: a congregation’s scanned registers, a historical society’s digitization project, a family historian’s twenty years of research, a small nonprofit’s entire operating history — all of it on one external drive, with the paper originals fragile, restricted, or long gone. When that drive fails, the loss is the same kind of loss those houses spent three hundred years preventing.