(ANALYSIS) As millions of Americans sit down to a turkey dinner with all their favorite sides, many will pause to say a prayer or otherwise give thanks. The one central theme to the holiday that endures to this day is the idea of giving God thanks. It’s the reason why the Pilgrims held a feast in the first place a year after making landfall in what is now Plymouth, Mass.

Even as a growing number of young people do not identify with any religion, Americans are still largely thankful to God. While the day is marked with football games and parades, it’s also true that Thanksgiving, one of the least commercial holiday’s celebrated in America, has a religious origin that has been debated ever since the Pilgrims marked the original Thanksgiving dinner in 1621 following their first harvest.

At the 400th anniversary of the holiday, historians and scholars continue to debate what the feast continues to mean for Americans. Thanksgiving, while rooted in religious tradition, remains one of the ties modern secular society has to this country’s colonial past. More than a Protestant holiday despite its roots, Thanksgiving is celebrated by all denominations and viewed as uniquely American.

The day we now call Thanksgiving was observed by the Pilgrims and the Wampanoag Indians in October 1621. The feast lasted three days and, according to attendee Edward Winslow, was attended by 90 Native Americans and 53 Pilgrims. The Pilgrims, like the colonists who followed them, celebrated a thanksgiving several times a year when the harvest was plentiful. It was highlighted by attending church services and thanking God before a large meal. Throughout the American Revolution, a day was set aside for giving thanks. Connecticut was the first to do so. The biggest change by the 17th century was that politicians were the ones calling for a Thanksgiving rather than church authorities.

Thanksgiving has endured, over the centuries, waves of immigration and wokeness — even though the way the holiday is taught in American classrooms has changed in recent years. The reason may be that this uniquely American tradition has a universal meaning to everyone, regardless of faith, place of birth or religion — or lack thereof.

“This is a day we are asked to give thanks to whatever supreme being we believe in as well as our families,” said Melanie Kirkpatrick, a senior fellow at the Hudson Institute and author of the book “Thanksgiving: The Holiday at the Heart of the American Experience.” “That goes back to our early history where we had to come together to survive.”

Pilgrims arriving to Massachusetts sought a religious freedom but differed from one another. The Pilgrims — a majority of whom were Separatists — sailed on the Mayflower and settled in Plymouth. A few years later, the Puritans would go on to establish their own Massachusetts Bay Colony in what is today Boston. Both groups were Calvinists but differed in their views regarding the Church of England. Puritans wished to remain in the Anglican Church and reform it; the Pilgrims wanted complete separation from the church.

William Bradford, governor of the Plymouth Colony at the time, wrote the following regarding the first Thanksgiving:

They began now to gather in the small harvest they had, and to fit up their houses and dwellings against winter, being all well recovered in health and strength and had all things in good plenty. For as some were thus employed in affairs abroad, others were exercised in fishing, about cod and bass and other fish, of which they took good store, of which every family had their portion. All the summer there was no want; and now began to come in store of fowl, as winter approached, of which this place did abound when they can be used (but afterward decreased by degrees). And besides waterfowl there was great store of wild turkeys, of which they took many, besides venison, etc. Besides, they had about a peck a meal a week to a person, or now since harvest, Indian corn to the proportion. Which made many afterwards write so largely of their plenty here to their friends in England, which were not feigned but true reports.

Bradford’s account never used the word thanksgiving. Kirkpatrick noted that for the Pilgrims, “that was not what they would have seen as a thanksgiving. That would have been a day set aside for worship.”

In the ensuing decades, the celebration would take on supreme importance after the colonies won the war of independence against Great Britain. On Oct. 3, 1789, former President George Washington formalized it and issued a proclamation calling Thursday, Nov. 26 of that year a day for “public thanksgiving and prayer.” It was the first time any nation in history had set aside such a day. This is what the proclamation said:

Whereas it is the duty of all Nations to acknowledge the providence of Almighty God, to obey his will, to be grateful for his benefits, and humbly to implore his protection and favor, and whereas both Houses of Congress have by their joint Committee requested me "to recommend to the People of the United States a day of public thanksgiving and prayer to be observed by acknowledging with grateful hearts the many signal favors of Almighty God especially by affording them an opportunity peaceably to establish a form of government for their safety and happiness.

Now therefore I do recommend and assign Thursday the 26th day of November next to be devoted by the People of these States to the service of that great and glorious Being, who is the beneficent Author of all the good that was, that is, or that will be. That we may then all unite in rendering unto him our sincere and humble thanks, for his kind care and protection of the People of this Country previous to their becoming a Nation, for the signal and manifold mercies, and the favorable interpositions of his providence, which we experienced in the course and conclusion of the late war, for the great degree of tranquility, union, and plenty, which we have since enjoyed, for the peaceable and rational manner, in which we have been enabled to establish constitutions of government for our safety and happiness, and particularly the national One now lately instituted, for the civil and religious liberty with which we are blessed; and the means we have of acquiring and diffusing useful knowledge; and in general for all the great and various favors which he hath been pleased to confer upon us.

And also that we may then unite in most humbly offering our prayers and supplications to the great Lord and Ruler of Nations and beseech him to pardon our national and other transgressions, to enable us all, whether in public or private stations, to perform our several and relative duties properly and punctually, to render our national government a blessing to all the people, by constantly being a Government of wise, just, and constitutional laws, discreetly and faithfully executed and obeyed, to protect and guide all Sovereigns and Nations (especially such as have shown kindness unto us) and to bless them with good government, peace, and concord. To promote the knowledge and practice of true religion and virtue, and the encrease of science among them and Us, and generally to grant unto all Mankind such a degree of temporal prosperity as he alone knows to be best.

Given under my hand at the City of New York the third day of October in the year of our Lord 1789.

Spanish colonists to the New World decades earlier had set aside days to give thanks upon arrival to what would become the United States. However, the notion of an annual harvest feast never really stuck. The holiday made a strong return in 1863 — during the midst of the Civil War — when former President Abraham Lincoln issued a national Thanksgiving proclamation.

In it, Lincoln wrote, “To these bounties, which are so constantly enjoyed that we are prone to forget the source from which they come … the ever watchful providence of Almighty God.” It wasn’t until 1941 that former President Franklin D. Roosevelt officially signed the day into law. In doing so, he called it an “observation in prayer.” Every presidential proclamation since has included a reference to God.

Thanksgiving, for many Americans, remains a day that includes prayer. For most Americans, it could be the only day they pray before a meal. It has also become a day set aside for parades and football games and a prelude to Black Friday sales and the Christmas season.

How did that happen? These traditions aren’t new. Originally called the “Christmas Parade,” Macy’s department store in New York launched its first-ever parade on Thanksgiving Day in 1924. College football games played on Thanksgiving date back to the late 1800s. The NFL’s tradition of football games played on that day started in 1934.

“In every century there has been controversy regarding what should be the centerpiece of the holiday and the giving thanks to God,” Kirkpatrick said. 

In the book, “The First Thanksgiving: What the Real Story Tells Us About Loving God and Learning From History,” author Robert Tracy McKenzie wrote, “I genuinely admire the Pilgrims, the group we commonly link to Thanksgiving’s origins. They had their blind spots — as we all do — but they were also people of faith, courage and hope, and there is much in their example to teach, admonish and inspire us.”

McKenzie, a history professor at Wheaton College, added, “We live in a time and place in which thinking deeply about the past is countercultural and even a radical act. Ours is a present-tense society.”

Former House Speaker Newt Gingrich, in a column posted to foxnews.com, said the Pilgrims remain relevant because “American history has left indelible marks on this American holiday. Yet despite nearly 400 years of history, today’s Thanksgiving still reflects the American values of the holiday as the Pilgrims originally celebrated it in 1621: a spirit of gratefulness, hospitality, time with friends and family, bountiful food, and generosity to those in need.”

In an age when historical figures — most notably Italian explorer Christopher Columbus and even recent ones like former President Ronald Reagan — are undergoing a reckoning, why does Thanksgiving endure? The Pilgrims, indeed, aren’t immune to such criticism. Nonetheless, Kirkpatrick said there is one main reason why Americans continue to celebrate Thanksgiving.

“They love the holiday so much that they don’t want to give it up,” she said.

Clemente Lisi is a senior editor and regular contributor to Religion Unplugged. He currently teaches journalism at The King’s College in New York City.