The history of Thanksgiving in Canada can be traced back to the 1578 voyage of Martin Frobisher from England in search of the Northwest Passage. His third voyage, to the Frobisher Bay area of Baffin Island in the present Canadian Territory of Nunavut, set out with the intention of starting a small settlement. His fleet of 15 ships was outfitted with men, materials, and provisions. However, the loss of one of his ships through contact with ice along with much of the building material was to prevent him from doing so. The expedition was plagued by ice and freak storms which at times had scattered the fleet and on meeting together again at their anchorage in Frobisher Bay, “… Mayster Wolfall, [ Robert Wolfall ] a learned man, appointed by her Majesties Councell to be their minister and preacher, made unto them a godly sermon, exhorting them especially to be thankefull to God for their strange and miraculous deliverance in those so dangerous places …”. They celebrated Communion and “The celebration of divine mystery was the first sign, scale, and confirmation of Christ’s name, death and passion ever known in all these quarters.”
Frobisher returned to England in the fall of the year with over a thousand tons of what he thought was precious gold ore which turned out to be totally worthless, and minus “fortie”, or about ten percent of his ships’ complement “which number is not great, considering how many ships were in the fleet, and how strange fortunes we passed.”
The exact locations of Frobisher’s activities remained a bit of a mystery until the discoveries of the American explorer Charles Francis Hall in Baffin Island nearly three centuries later in 1861.
Years later, French settlers, having crossed the ocean and arrived in Canada with explorer Samuel de Champlain, in 1604 onwards 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, with New France handed over 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 newly independent United States and came to Canada. They brought the customs and practices of the American Thanksgiving to Canada, such as the turkey, pumpkin, and squash.
Lower Canada and Upper Canada observed Thanksgiving on different dates; for example, in 1816 both celebrated Thanksgiving for the termination of the war between France and Great Britain, the former on May 21 and the latter on June 18. In 1838, Lower Canada used Thanksgiving to celebrate the end of the Lower Canada Rebellion. Following the rebellions, the two Canadas were merged into a united Province of Canada, which observed Thanksgiving six times from 1850 to 1865.
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.
For many years before it was declared a national holiday in 1879, Thanksgiving was celebrated in either late October or early November. From 1879 onward, Thanksgiving Day has been observed every year, the date initially being a Thursday in November. The date of celebration changed several times until, in 1957, it was officially declared to be the second Monday in October. The theme of the Thanksgiving holiday also changed each year to reflect an important event to be thankful for. In its early years it was for an abundant harvest and occasionally for a special anniversary.
After World War I, an amendment to the Armistice Day Act established that Armistice Day and Thanksgiving would, starting in 1921, both be 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. From 1931 to 1957, the date was set by proclamation, generally falling on the second Monday in October, except for 1935, when it was moved due to a general election. In 1957, Parliament fixed Thanksgiving as the second Monday in October.
Source material from Wikipedia, and from “A Puritan Mind.”