Abraham Lincoln, in 1863, declared the last Thursday in November be celebrated as a national day of Thanksgiving. Most of us remember being taught differently.
Fifty three surviving members of the English colony Plymouth Plantation in Massachusetts celebrated their successful harvest in 1621 by providing a lavish meal for themselves and around ninety natives of the Wampanoag, including the teacher Squanto and Chief Massasoit. Both English and American natives traditionally held a harvest feast at the end of the growing season and this was to be no exception.
The affair was celebrated two years later after a "million dollar" rainfall saved their crops, and although the word thanksgiving was used, the day, as before, was purely religious in nature.
The actual national holiday to be held on the last Thursday of November came 240 years later when Thanksgiving Day was proclaimed on October 3, 1863 while war raged, by none other than Abraham Lincoln, exactly seventy four years after the first presidential recognition.
...In the midst of a civil war of unequaled magnitude and severity, which has sometimes seemed to foreign States to invite and to provoke their aggression, peace has been preserved with all nations, order has been maintained, the laws have been respected and obeyed, and harmony has prevailed everywhere except in the theatre of military conflict; while that theatre has been greatly contracted by the advancing armies and navies of the Union.
There had been other presidential proclamations, to be sure. George Washington is the "first" in a lot of catagories and on October 3, 1789 he issued the first Thanksgiving proclamation for that year only, revisiting the idea six years later in 1795.
There have been declarations by many presidents and governors but none stuck until Abraham Lincoln's Proclamation. At the urging of Sarah Josepha Hale, among others, he issued the proclamation in the autumn after the savage Battle of Gettysburg. The soldiers, including our own, mangled, 1st Minnesota Infantry Regiment were, no doubt, grateful recipients of extra rations.
I do therefore invite my fellow citizens in every part of the United States, and also those who are at sea and those who are sojourning in foreign lands, to set apart and observe the last Thursday of November next, as a day of Thanksgiving...
It is said that one year later, Lincoln, agonizing over the barbarity of both sides in the seemingly unending battles around Petersburg ordered a one day ceasefire and rations issued of canned turkey...for both sides.
Dr. Bob Beltz, the national Faith and Culture Examiner has further insights about the Civil War Thanksgiving.