Another government-sponsored Canada Day push came with the centennial in 1967. As I wrote this week, its signature event was Expo 67, the wildly successful world’s fair in Montreal. The 150th anniversary has not brought anything on the scale of Expo. Instead the government is promising just a bigger and better slate of the usual fireworks and entertainment for the main celebrations in Ottawa. And since it’s 2017, that includes more security.

Often Canada Day is described as Canada’s birthday, although it doesn’t really mark the start of a fully independent nation. On July 1, 1867, a law from the United Kingdom, the British North America Act, set up the federal government and joined three of its colonial provinces: New Brunswick, Nova Scotia and Canada (which was divided into Ontario and Quebec that day) into the Dominion of Canada. A federal government was placed atop of them to create a confederation. But Britain still retained some legislative and legal controls, ran foreign affairs and kept Canadians as its subjects.

Why did confederation take place on July 1, 1867? Queen Victoria signed the British North America act on March 29, 1867, and the law gave everyone over in Canada six months to prepare before it came into effect. On May 22, it was officially proclaimed that July 1 would be the big day.

I asked several historians, including Professor Cupido, why that day was chosen. They didn’t know. The Department of Canadian Heritage, which is in charge of the Canada 150 celebrations, drew a blank. And the research branch at the Library of Parliament, which is currently displaying one of the original copies of the B.N.A. Act, replied that “there doesn’t appear to be a clear reason for the choice of date.”

Perhaps it was simply because the arrangements were all in place by July 1. Or maybe it was because the fiscal year of the former province of Canada ended on June 30. Ah, the workings of bureaucracy.