‘Canada emerged late from the Victorian period’, declared historian John Webster Grant about the 1960s. ‘And how!’ we might say, six decades later. From the time of Confederation in 1867, Canada was among the world's most observant Christian countries, whose national motto (‘From Sea to Sea’) came from the Bible and implied God's dominion over the land (Psalm 72: 8), and whose day-to-day life was shaped in large part by the Christian church year. Within a few decades of Canada's centennial celebration in 1967, it was fast becoming one of the most secular countries in the world.

Canada indeed emerged late from a millennium and more of European Christendom: the official – or all-but-official – sanctioning of Christianity as the religion of the state, nation and society. Michael Gauvreau has termed the era beginning around Confederation and lasting until the 1960s Canada's ‘evangelical century’, and the cultural dominance of Roman Catholicism in Francophone Canada paralleled the influence of observant Protestantism in the rest of the country. Over the course of the first half of the nineteenth century, Canada went from being a country of colonists and native peoples who rarely, if ever, attended church to a country with one of the highest rates of regular churchgoing in the West. From the 1860s to the 1960s, two-thirds or more of Canadians attended church weekly, and the 1961 census recorded 96% of Canadians calling themselves Christians.

The largest religious bloc of Canadians, then and now, has been Roman Catholics: in Quebec overwhelmingly so, although in Anglophone Canada Catholic churches have maintained the nominal allegiance of about a third of the population. The Orthodox churches have made up 3–4% of the population. The Protestant sector used to take up the rest.

Canadian Protestantism has been constituted by two main groups: the four so-called mainline churches and then the congeries of groups known as Evangelicals. The two largest denominations have been the Anglican Church of Canada and the United Church of Canada (the latter formed in 1925 from an ecumenical combination of most Methodists, all the Congregationalists and roughly two-thirds of the Presbyterians). The remaining churches with a ‘state church’ heritage were the Presbyterians and Lutherans.