The Lieutenant Governor of Upper Canada, John Graves Simcoe had been a supporter of the abolition of slavery while a Member of Parliament, before coming to Canada. Upper Canada had about 300 slaves in early 1790’s.
In an Executive Council meeting in March 1793 Simcoe heard testimony from a witness, Peter Martin about a female slave; Chloe Cooley who had been violently taken from Canada to be resold in United State. Cooley who was from Queenston, had been bound, thrown in a boat and she was sold across the river in the United States. Simcoe used this story as way to push for an Act to abolish slavery. The Act was opposed by many members of the House of Assembly, of whom 6 of the 16 owned slaves. They reached a compromise on July 9th 1793.
Titled “An Act to Prevent the Further Introduction of Slaves and to Limit the Term of Contracts for Servitude with the Province”, it read that all slave currently in the province would remain slaves, no new slaves could be brought into the Province, and any children born to a slave would be freed at the age of 25.
If you would like to read more about this topic, look at AN ACT TO PREVENT THE FURTHER INTRODUCTION OF SLAVES