Britain banned the institution of slavery in present-day Canada (and British colonies) in 1833, though the practice of slavery in Canada had effectively ended already early in the 19th century through case law, due to court decisions resulting from litigation on behalf of slaves seeking manumission. The courts, to varying degrees, rendered slavery unenforceable in both Lower Canada and Nova Scotia. In Lower Canada, for example, after court decisions in the late 1790s, the "slave could not be compelled to serve longer than he would, and ... might leave his master at will." Upper Canada passed the Act Against Slavery in 1793, one of the earliest anti-slavery acts in the world.