In 1620 a band of religious separatists who weren’t happy with their situation in England (Church of England) or Amsterdam or Leiden (cultural influences) departed for the New World. For some reason, they planned their trip such that they arrived in Massachusetts in December. They found land that had been cleared by a prior Indian settlement and subsequently decimated by disease — most likely smallpox — and were able to settle there during the winter.
Fortunately, a native Patuxet named Squanto who had twice been kidnapped and enslaved by Englishmen was able and willing to translate for the Pilgrims and teach them how to raise corn and catch eel. Having survived their first year by the skin of their teeth and brought in their first harvest, the Pilgrims celebrated their first Thanksgiving 386 years ago.
So, today, as you enjoy your turkey and mashed potatoes and what have you, give thanks to God and/or Squanto as your preferences dictate.