Here is an excerpt from Wikipedia on the history of Canadian Thanksgiving. I think this is so interesting and I had never heard any of this stuff before. My excuse? The year I graduated from high school (2000) was the very first year a Canadian history class was offered at my high school. Before it was all Social Studies, Humanities, Media Studies and other classes with strange names and oddly imbalanced teachings. The year AFTER I graduated, Canadian History became a mandatory credit.
The history of Thanksgiving in Canada goes back to an explorer, Martin Frobisher, who had been trying to find a northern passage to the Orient. In the year 1578, he held a formal ceremony, in what is now the province of Newfoundland and Labrador, to give thanks for surviving the long journey. The feast was one of the first Thanksgiving celebrations in North America, although celebrating the harvest and giving thanks for a successful bounty of crops had been a long-standing tradition throughout North America by various First Nations and Native American groups. First Nations and Native Americans throughout the Americas, including the Pueblo, Cherokee, Cree and many others organized harvest festivals, ceremonial dances, and other celebrations of thanks for centuries before the arrival of Europeans in North America. Frobisher was later knighted and had an inlet of the Atlantic Ocean in northern Canada named after him — Frobisher Bay.
At the same time, French settlers, having crossed the ocean and arrived in Canada with explorer Samuel de Champlain, also held huge feasts of thanks. They even formed 'The Order of Good Cheer' and gladly shared their food with their First Nations neighbours.
After the Seven Years' War ended in 1763 handing over New France to the British, the citizens of Halifax held a special day of Thanksgiving. Thanksgiving days were observed beginning in 1799 but did not occur every year. After the American Revolution, American refugees who remained loyal to Great Britain moved from the United States and came to Canada. They brought the customs and practices of the American Thanksgiving to Canada. The first Thanksgiving Day after Canadian Confederation was observed as a civic holiday on April 5, 1872 to celebrate the recovery of the Prince of Wales (later King Edward VII) from a serious illness.
Starting in 1879 Thanksgiving Day was observed every year but the date was proclaimed annually and changed year to year. The theme of the Thanksgiving holiday also changed year to year to reflect an important event to be thankful for. In the early years it was for an abundant harvest and occasionally for a special anniversary.
After World War I, both Armistice Day and Thanksgiving were celebrated on the Monday of the week in which November 11 occurred. Ten years later, in 1931, the two days became separate holidays, and Armistice Day was renamed Remembrance Day.
On January 31, 1957, the Canadian Parliament proclaimed:
"A Day of General Thanksgiving to Almighty God for the bountiful harvest with which Canada has been blessed … to be observed on the 2nd Monday in October."