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.
Following the Stono Rebellion (1739), South Carolina banned importation of slaves from the Kongo region. Planters ignored this by landing cargoes in Georgia first, then smuggling them across the Savannah River at night—a violation of customs law and the 1740 Negro Act. skacat illegal aspects of legal slavery 18 best
If an owner ordered a slave to commit theft, arson, or murder, the owner was often held criminally liable (at least in Roman law and later common law). The slave might also be punished, but the master’s order could be illegal. In the US South, a white person could be indicted for “inciting a slave to rebellion” or “causing a slave to commit a felony” (e.g., poisoning a neighbor’s well). The Spanish asiento (contract to supply slaves to
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 slave owners granted manumission legally via will
In the post-1830 US South, teaching a slave to read was criminalized (e.g., South Carolina 1834, Virginia 1831). However, this illegal act was often committed by sympathetic whites or slaves themselves. Whether it was “illegal” depended on the jurisdiction. In earlier periods or other colonies, literacy was not banned. So the illegal nature varied by time/place—but where banned, literacy instruction became an underground illegal activity within a legal slave system.