Tomorrow, Americans celebrate a national holiday set aside to give thanks for the blessings of the preceding year. But there is more to Thanksgiving than you may realize. Here are five facts you should know about the holiday:

1. The Pilgrims who traveled on theMayflowerand landed on Cape Codwere not the first Americans to celebrate Thanksgiving. The “Feast of the First Thanksgiving” was held near El Paso, Texas in 1598 — twenty-three years before the Pilgrims’ festival. And at the Berkeley Plantation on the James River in Virginia, settlers celebrated Thanksgiving on December 4th, 1619 — two years before the Pilgrims’ festival. As historian Robert Tracy McKenzie, author of The First Thanksgiving, notes, the early Plymouth settlers celebrated in 1621 could more accurately be called the “First American Protestant Christian Thanksgiving North of Virginia and South of Maine.”

2. The first Thanksgiving at Plymouth was a secular event that was not repeated. (A Calvinist Thanksgiving occurred in 1623 and did not involve sharing food with the Native Americans.) 52 Pilgrims and approximately 50 Native Americans attended that celebration. According to participant Edward Winslow, the feast consisted of corn, barley, fowl (including wild turkeys), and venison.

3. Sarah Josepha Hale, an editor and the author of the classic nursery rhyme “Mary Had a Little Lamb”, is the person most responsible for making Thanksgiving a national holiday. Prior to 1863, the holiday was largely a celebration held in New England and unknown in the Southern states. Hale proposed that it be a national holiday in 1846 and advocated it for 17 years before convincing Abraham Lincoln to support legislation establishing a national holiday of Thanksgiving in 1863.

4. For 75 years after Lincoln issued his Thanksgiving Proclamation, succeeding presidents honored the tradition and annually issued their own Thanksgiving Proclamation, declaring the last Thursday in November as the day of Thanksgiving. However, in 1939 the last Thursday of November was going to be November 30. plained to President Franklin D. Roosevelt that this only left 24 shopping days to Christmas and convinced him to move Thanksgiving up one week earlier. Since it was believed most people do their Christmas shopping after Thanksgiving, retailers thought having an extra week of shopping would encourage Americans to spend more.

5. Each year the President officially declares a day of National Thanksgiving and every president Since Harry Truman has pardoned a turkey for Thanksgiving.