 From 1942 onwards, Thanksgiving, by an act of Congress, signed into law by FDR, received a permanent observation date, the fourth Thursday in November, no longer at the discretion of the President.Setting aside time to give thanks for one's blessings, along with holding feasts to celebrate a harvest, are both practices that long predate the European settlement of North America.The first documented thanksgiving services in territory currently belonging to the United States were conducted by Spaniards and the French in the 16th century.