When the Mayflower pilgrims and the Wampanoag sat down for the first Thanksgiving in 1621, it wasn’t actually that big of a deal. Likely, it was just a routine English harvest celebration. More significant—and less remembered—was the peace treaty that the parties established seven months earlier, which lasted for 50 years. (See also: National Geographic Kids: First Thanksgiving.)

“There’s in fact very little historical record of the first Thanksgiving, which is why Thanksgiving wasn’t really celebrated as a holiday until the 19th century,” says Charles C. Mann, author of 1491: New Revelations of the Americas Before Columbus. “To historians, it seems kind of funny that the celebration … now seems more important than the treaty itself.”

President Abraham Lincoln