Slaves were property. Therefore, damaging another person’s slave was a tort (or crime) similar to damaging cattle.
The illegal aspect: unauthorized physical interference.
Though the British Slave Trade Act of 1807 is famous, several 18th-century colonial assemblies passed earlier, weaker prohibitions—often ignored. For example, Rhode Island’s 1774 act banning slave importation was routinely flouted by merchants who filed false manifests, listing enslaved Africans as “indentured servants” or “cargo samples.” skacat illegal aspects of legal slavery 18 best
Many colonies taxed slave births or population increases. Owners who failed to register newborn slaves committed fraud, an illegal act. In Jamaica (18th century), planters would sometimes conceal births to avoid duties—these men could be fined or even imprisoned.
Slave owners insured enslaved people for high sums, then killed them by starvation or overwork and claimed accidental death. British marine insurance law of 1745 explicitly forbade insuring a person in whom the policyholder had no legitimate interest beyond profit from death—exactly what planters did. Slaves were property
Some slave owners granted manumission legally via will or deed, then had heirs illegally re-enslave the freed person by claiming “ingratitude” or destroying documents. Virginia’s 1782 manumission law was routinely circumvented this way, though such actions were illegal under property and contract law.
Some colonies (e.g., Massachusetts Bay, 1703) allowed branding only for convicted runaway slaves. Yet masters branded faces, foreheads, and breasts for minor offenses like “sullenness.” This was unlawful cruel punishment outside judicial sentencing. The illegal aspect: unauthorized physical interference
The Spanish asiento (contract to supply slaves to Spanish colonies) was repeatedly violated by British smugglers. The 1713 Treaty of Utrecht legalized only 144,000 slaves over 30 years; actual shipments were triple that, with undeclared cargoes hidden behind “dry goods” labels—a violation of international treaty obligations.