According to Joanne Braxton and Maria Diedrich in Monuments of the Black Atlantic, John Jack was once owned by Benjamin Barron of Concord. He bought his freedom and a small farm in 1761. Jack's wonderful epitaph was written by Daniel Bliss, a noted Tory and abolitionist who was forced to flee Massachusetts during the Revolution. John Jack's epitaph reads:
God wills us free, man wills us slaves.
I will as God wills Gods will be done.
Here lies the body of
A native of Africa who died
March 1773. aged about 60 years
Tho' born in a land of slavery,
He was born free.
Tho' he lived in a land of liberty,
He lived a slave,
Till by his honest, tho' stolen labors,
He acquired the source of slavery,
Which gave him his freedom;
Tho' not long before
Death the grand tyrant,
Gave him his final emancipation,
And set him on a footing with kings.
Tho' a slave to vice,
He practised those virtues
Without which kings are but slaves.