For a holiday based on a Biblical event 2,000 years ago, many Christmas traditions are relatively new. While “Merry Christmas” can be traced back to the 16th century, a carol like “Do You Hear What I Hear?” only dates back to the 1960s, inspired by the Cuban Missile Crisis. Several traditions came about entirely by accident, like NORAD Santa Tracker, which started with a misprint in a newspaper. Others are products of wartime, and such rituals have helped bring people together during precarious times.

Here, are some of the most surprising stories behind popular Christmas rituals.

“Merry Christmas” greetings

Brian Earl’s Christmas Past: The Fascinating Stories Behind Our Favorite Holiday’s Traditions traces the first known instance of “Merry Christmas” to a 16th-century letter from a bishop to England’s Chief Minister, in which the religious leader hoped God would bless the politician with a “Merry Christmas.” The carol “God Rest Ye Merry, gentlemen” also dates back to that period and is proof that the phrase was gaining popularity.

But Charles Dickens’ A Christmas Carol popularized the phrase the most because it was a bestseller when it was published in 1843. At one point, Scrooge’s nephew exclaims “A Merry Christmas, uncle! God save you!” In that same period, the first commercially printed Christmas cards started coming out with the phrase “Merry Christmas.”

The TV Yule Log

Americans without a fireplace can just turn on their TVs at Christmastime and get an hours-long loop of a burning log, often with a soundtrack of Christmas carols.

The first televised yule log dates back to 1966, filmed at a fireplace in Gracie Mansion, then the home of New York City Mayor John Lindsay. The TV station WPIX found itself short on programming on Christmas Eve, and just headed down to the mayor’s house, where it broadcast full-color footage of his fireplace at 9:30 p.m.