1621: The first Thanksgiving at Plymouth, Massachusetts, lasted three days.
1639: Although records from the early years are incomplete, a proclamation of thanksgiving for September 1639 survives, as do proclamations for 1644 and for every year from 1649 onwards.
1775: Thanksgiving Day was celebrated by the Continental Army besieging the British troops in Boston.
1777: Thanksgiving was for the first time proclaimed by a national authority, the Continental Congress, for all 13 states. It was kept on Dec. 18 by Gen. George Washington and his troops at Valley Forge, Pennsylvania.
1863: President Abraham Lincoln established the national holiday of Thanksgiving on the last Thursday of November. At that time, Abraham Lincoln warned, "We have been recipients of the choicest bounties of Heaven... we have grown in numbers, wealth and power as no other nation has ever grown, but we have forgotten God."
He then restored the neglected presidential proclamations of prayer and thanksgiving during the tragic years of the Civil War. "Intoxicated with unbroken success," he wrote, "we have become too self-sufficient to feel the necessity of [God's] redeeming and preserving grace, too proud to pray to the God that made us."
Then he issued the first Thanksgiving Proclamation, establishing a date for Thanksgiving on the last Thursday of November (later changed to fourth Thursday).