sentences:  John Mason, a southerner, ruled that, since most of the Black Seminoles were descendants of fugitive slaves and thus legally still considered born into slavery, Jesup's decree had illegally deprived their Seminole owners of their legal property and could not be endorsed by the government.Thus the very reason many of the blacks had agreed to come in peacefully, and which had so seriously undermined the Seminoles' fight to remain in Florida, was suddenly and retroactively revoked.Seminole practice in Florida had acknowledged slavery, though not on the chattel slavery model then common in the American south.