Thanksgiving is an annual American holiday celebrated by families, friends and magazines. Yes. Magazines. In fact, you could say our current version of Thanksgiving was invented by a magazine or more specifically a magazine editor.
Around this time every year, historians regale us with stories of what the first Thanksgiving was really like. We learn that it was unlikely they ate a stuffed turkey, there was no pumpkin pie, no cranberry sauce, and most of the food was provided by the Wampanoag not the pilgrims--who feasted on venison, lobsters, clams, oysters, and fish.
Harvest festivals were a long standing tradition for the Wampanoag natives going back way before the arrival of the pilgrims. The pilgrims and colonists, devout Christians, observed many days of "thanksgiving" throughout the year in which prayer and fasting were the order of the day, not feasting.
The first national Thanksgiving was held in December of 1777 by colonists to celebrate the surrender of British General Burgoyne at Saratoga. But Thanksgiving was not celebrated consistently all over the country until much, much later.