A fugitive from slavery, Arthur Cooper (1798-1853) arrived in Nantucket with his family in 1820. Two years later when an agent for his former owner came to the island to claim him, Nantucket Quakers assisted their escape.
From the Nantucket Historical Association:
A crowd of blacks and Quakers pledged that they would not let the
family be removed. William Mitchell, father of Maria Mitchell, organized
a citizens’ response. While he explained to Griffith that he had no
authority to apprehend the Coopers, another townsperson slipped the
family out the back door. When the matter was brought before him,
Magistrate Alfred Folger ruled that the family could not be removed from
Nantucket, and Griffith left the island empty-handed. Griffith
continued trying to gain possession of the Coopers through litigation on
the mainland, but he was unsuccessful. The Coopers continued to live in
peace on Nantucket.