"Everyone seems to know the story of the first American Thanksgiving in 1621, but do you know how Canadian Thanksgiving came about? In fact, the first Canadian Thanksgiving may have even pre-dated the Pilgrims’ big meal.

The tradition of Thanksgiving originated with the harvest festival—an autumnal celebration meant to show appreciation for the season’s bountiful harvest. However, Canadian Thanksgiving was initially less about celebrating the harvest and more about thanking God for keeping early explorers safe as they ventured into the New World.

In that sense of “thanks-giving,” the earliest report of such a dinner dates back to 1578 when English explorer Martin Frobisher and his crew held a special meal to thank God for granting them safe passage through northern North America into what is today the Canadian Territory of Nunavut. "

From "4 Ways Canadian Thanksgiving differs from American Thanksgiving" www.almanac.com