Reform movement (pre-Confederation Canada)
In Upper Canada (Ontario), the Reform movement was formed in opposition to the Family Compact. It was led initially by William Lyon Mackenzie, who became the principal figure in the Upper Canada Rebellion of 1837. Mackenzie went into exile as a result of the failed rebellion. The uprising led to the 1839 Durham Report, which recommended responsible government and the union of Upper and Lower Canada as a means of assimilating Francophones. Only the union of the Canadas was to be immediately implemented.
Legislative Assembly of Upper Canada
Following the war, the Executive and Legislative Councils became increasingly dominated by the Family Compact, a clique of wealthy individuals led primarily by John Strachan (a member of the powerful Executive Council of Upper Canada), which emerged in 1815. The Compact was deeply opposed to American republicanism and favoured full establishment for the Anglican church in Upper Canada. Their increasingly authoritarian style of governance and disregard for the will of the Legislative Assembly led to demands for government that was more responsible to the people and eventually the Upper Canada Rebellion of 1837. Opposing the Family Compact were initially an assortment of anti-establishment members, but it did not gain strength until a more formal group of reformers emerged, initially led by William Warren Baldwin starting 1820s and then by William Lyon Mackenzie in the 1830s.