It is the kind of mystery that bedevils museum collections everywhere.
But for the Museum of the American Revolution, this one is particularly intriguing.
On the underside of the roof of Gen. George Washington's weathered, linen field tent, unviewable by the public, is a stamped symbol that bears a resemblance to ancient Arabic calligraphy.
It's not unusual to find a stamp on old linen fabric. It might indicate the manufacturer or where the cloth was made or inspected. But this stamp is unlike anything members of the museum's professional staff have encountered before.
Is it a stamp of origin? If so, from where? Who made it?
Museum experts have consulted counterparts around the country and in Europe. No one has seen anything like this stamp.
One professional has said it resembles ancient Arabic. But the Arabic Studies Center at the College of William and Mary has not been able to identify the symbol.