Think you know everything about the real story of Thanksgiving? See whether you've been taken in by any of these Thanksgiving myths.

Myth: All that tryptophan in turkey makes diners fall asleep after their Thanksgiving feasts.

Fact: Turkey does contain some tryptophan, which our bodies use to make serotonin, which can turn into melatonin, which triggers sleep -- but turkey doesn't contain nearly enough tryptophan to induce that much serotonin production.

Myth: President Abraham Lincoln started the tradition of pardoning a turkey every Thanksgiving.

Fact: There is a tale about Lincoln sparing a Christmas a turkey at his son's request, but it was President George H.W. Bush who first officially pardoned a turkey in 1989, according to The White House. 

Myth: The Pilgrims were trying to land in Virginia, but settled in Massachusetts by mistake.

Fact: The Mayflower was headed to New York's Hudson River region, which was a part of the Virginia Company's land at the time. Bad weather forced them farther north to Cape Cod, according to the History Channel.

Myth: Turkey was served at the first Thanksgiving, and that tradition continues today.

Fact: There were wild turkeys around, but it's more likely the centerpiece of the meal was venison. The modern Thanksgiving meal was popularized by Sarah Josepha Hale, editor of the women's magazine Godey's Lady's Book in the mid-1800s.

Myth: Thanksgiving has always been on the fourth Thursday of November.

Fact: The Pilgrims' feast was a three-day festival sometime between late September and early October. Congress approved President Franklin Roosevelt's desire to set it on the fourth Thursday of November in 1941, according to The History Channel.