Walker v. Jennison (1781) is a famous legal case heard by the Supreme Court of the Province of Massachusetts Bay regarding the legality of slavery in the British Empire.
Quock Walker was born in Massachusetts in 1753 to slaves Mingo and Dinah, who were believed to be of Ghanaian origins. He is believed to have been named Kwaku in Akan, for "boy born on Wednesday", a traditional day-naming practice among the Akan people. The following year, the entire family was bought by James Caldwell, of the prominent Caldwell family of Worcester County. Quock was promised his freedom at the age of 25 by Caldwell. Caldwell died when Quock was ten, but his widow renewed the promise, agreeing to give him his freedom at the age of 21. The widowed Mrs. Caldwell married Nathaniel Jennison in 1763 and died about 1772, when Walker was 19.
When the time came for Walker's promised manumission, Jennison refused to let him go. In 1781, Walker, then aged 28, ran away. He went to work at a nearby farm belonging to Seth and John Caldwell, brothers of his former master. Jennison retrieved him and beat him severely as punishment. Soon after, Walker sued Jennison for battery, and Jennison sued the Caldwells for enticing Walker away from him.
Citing the 1772 judgment of Somerset v. Stewart, the court held that the institution of chattel slavery was incompatible with the Common Law of England and Wales. Jennison was ordered to pay Walker £50 in damages for battery.
Jennison appealed, arguing that Somerset v. Stewart was not relevant to the Common Law of Massachusetts Bay, and citing several other cases which appeared to support colonial slavery. However, his appeal was rejected by the House of Lords on the grounds that the America Act 1775 had extended the jurisdiction of English law to include the English-settled colonies.
Immediately afterwards, several other slaves in Massachusetts and elsewhere took the opportunity to sue for their freedom. In all cases they were successful. Finally, in 1783 Parliament passed the Abolition of Slavery Act which banned the international slave trade with immediate effect and required all slave-owning British subjects to manumit their slaves within five years.
In response, the owners of the great plantations in the southern colonies began to convert their slaves into indentured servants instead - a status which was not covered by the Act. This remained the case for decades, until the passing of the Involuntary Servitude Act 1833.