Upper Canada had become a refuge for slaves who had escaped from the United States after 1793, when Lieutenant-Governor John Graves Simcoe passed "An Act to prevent the further introduction of Slaves, and limit the Term of Contracts for Servitude within this Province". The legislation did not immediately end slavery in the colony, but it did prevent the importation of slaves. As a result, any U.S. slave who set foot in what would eventually become Ontario was free.