Jose Pizarro, for the Kingdom of Spain, and Henry Wellesley, for the United Kingdom—without a war—sign the Treaty of Madrid prohibiting the further introduction of slaves into Cuba, Puerto Rico and Santo Domingo, thus banning the international slave trade in the Spanish Caribbean.
[added 12/17/2021]
Subsequent Events:
References:
Anglo-Spanish Anti-Slave trade Treaties etc.htm
www.pdavis.nl/Treaty_1817.htm
CHRONOLOGY: Who banned slavery when? | Reuters
www.reuters.com/article/idUSEIC16869120070321