"Queen Nzinga" promise to free all slaves in her kingdom.
EXPLANATION:
Queen Nzinga was a powerful African ruler of the 17th century, who fought for the freedom of the people of her kingdom against Portuguese. She had excellent negotiation skills with which she negotiated the military to contain the Portuguese colony to only a few square miles.
She was the most famous African woman who resisted European colonization, but she was a vicious slave trader. She supported the slave trade but then protected the escaped slaves because of their loyalty.