William Lyon Mackenzie
The township of York, which until 1793 had been known as "Toronto", incorporated as a city (meaning it received local self-government) on March 6, 1834, taking the name of "the City of Toronto" to distinguish it from New York City and the dozen other settlements named 'York' in Upper Canada. The Tories and the Reformers fielded candidates for Toronto's first municipal election, held on March 27, 1834, with the Reformers winning a majority on the Toronto City Council. Mackenzie was elected as an alderman. The City Council then met to decide who should become mayor. Mackenzie, after being nominated by Franklin Jackes, defeated John Rolph in the vote and thereby became the first Mayor of Toronto.
Greater Toronto Area
In 1816, Wentworth County and Halton County were created from York County. York County would later serve as the setting for the beginnings of the Upper Canada Rebellion with William Lyon Mackenzie's armed march from Holland Landing towards York Township on Yonge Street, eventually leading up to the battle at Montgomery's Tavern. In 1851, Ontario County (present-day Durham Region) and Peel County were separated from York.