Unveiling the Origins and Evolution of Thanksgiving
Thanksgiving became an official American holiday in 1789 when President George Washington issued a decree recommending a day of public thanksgiving and prayer. Washington's proclamation emphasized gratitude for the successful conclusion of the Revolutionary War, the establishment of the U.S. Constitution, and the blessings of civil and religious liberty. The holiday's date varied until President Abraham Lincoln set it as the last Thursday in November in 1863, a tradition largely maintained since, except for a brief change by Franklin D. Roosevelt in 1939.