The Family Compact developed after the War of 1812 and lasted until Upper and Lower Canada were united in 1841. In Lower Canada, its equivalent was the Château Clique. Members of the Family Compact were described as adherents of "rabid Toryism" by Charles Dickens during his visit to North America.
The Family Compact controlled the government through the Executive Council, the advisors to the Lieutenant Governor, leaving the popularly elected Legislative Council and Legislative Assembly with little real power. Members of the Family Compact ensured their conservative friends held the important positions in the colony through political patronage.
The Family Compact was centred in Toronto, then called York. Its most important member was Bishop John Strachan; in fact, many of the other members were his former students, or people who were in some way related to him. The rest of the members were mostly descendants of United Empire Loyalists or recent upper-class British settlers. With this Loyalist background and under the leadership of Strachan, they were strong royalists, and supported the Church of England over not only Catholicism but other Protestant churches. They especially interpreted the Constitutional Act of 1791, which gave land grants to build Protestant churches, to refer to Anglican churches alone. This was opposed by the large numbers of Presbyterian Scottish settlers, as well as smaller groups of Methodists.
The influence of the Family Compact was one of the chief concerns of radical reformer William Lyon Mackenzie. Mackenzie's frustration with their control of the government was one of the catalysts for the Upper Canada Rebellion of 1837. Their hold on the government was eliminated with the creation of the united Province of Canada under Lord Durham, who replaced Sir Francis Bond Head (a supporter of the Family Compact) as Lieutenant-Governor in 1838.