Washington brought eight slaves from Mount Vernon, Va., to Philadelphia to serve his presidential household from 1789 to 1797 - little-known history that has achieved prominence in recent months.
The first president's executive residence was the Morris Mansion, at 6th and Market streets - now part of Independence National Historical Park.
The mansion is long gone and its dimensions not precisely known. But it's clear that slave quarters behind the house were near the construction site for the new Liberty Bell Center.
Now a division of the Philadelphia Convention and Visitors Bureau is pushing for a "prominent monument or memorial" to tell about Washington's slaves and the local involvement with slavery and abolitionists.
The acting director of Independence Park, the object of the campaign, says no decisions have been made. But the issue, says Dennis Reidenbach, is not whether to interpret slavery at the old mansion site, but how to do it.
Tanya Hall, executive director of the bureau's Multicultural Affairs Congress, has tied the portrayal to her work in attracting black conventioneers and tourists. The slavery issue, she said, offers Philadelphia a great opportunity to cement its role as a leading destination for African-Americans.
While stopping short of warning of convention boycotts, she said there's a "downside if we don't do the right thing."
"Tourists, whether people of color or not, make educated decisions on where to travel," Hall said. "There are always eyes on Philadelphia, what we do and don't do."
In a letter Hall released that advocates a "prominent" memorial, she wrote, "It is our belief that a generic plaque or historical marker will not 'appropriately commemorate' those enslaved Africans."
Hall said her prime motive for urging a thorough airing of Washington's slaves at Independence Park is "economic." Other cities, she said, have followed Philadelphia's lead and actively compete for minority visitors.
Unspoken are the lessons from Arizona, which lost a Super Bowl and conventions before it agreed to honor Martin Luther King's birthday, and Southern states hit with boycotts tied to the display of the Confederate flag.
The multicultural congress, which has pioneered black-visitor recruitment, says the city has booked $600 million in African- American conventions since it was founded in 1987, while black tourism averages $80 million a year.
Surveys have shown people of color represent up to one quarter of the city's tourists and conventioneers.
Slavery is already a major part of the interpretation of history all across the park, says Reidenbach.
Deciding how that story will be told at the Morris Mansion site, he said, is "a process and we're at the very beginning stages." He's getting lots of help.
A new group called Avenging the Ancestors Coalition has flooded the park with more than 100 form letters insisting on a major monument to Washington's slaves at the new Liberty Bell site itself, not an "unrelated exhibition" or "mere panel."
The park has its own four-page form letter to clear up "misunderstandings." It says archeology at the bell site produced "no items related to distinctive African- American cultural practices."
Hall has met with Reidenbach and arranged meetings involving the Ancestors Coalition. The park has also met with historians and scholars who, Reidenbach said, are helping revise exhibit text for the Bell Center.
Construction has begun on the $13 million pavilion, which will place the bell near 6th and Chestnut, not over former slave quarters, closer to 6th and Market.