You know the songs, but you probably didn’t know these fun facts about them. When the carolers hit your house, regale them with some trivia about their tunes!

“I Saw Mommy Kissing Santa Claus”

The song is built around a joke that’s never completely explained, but that most listeners understand: A child witnesses his mother smooching St. Nick…as they’re too young and innocent to realize that Mommy is kissing Daddy dressed up like Santa Claus. Some people in the Boston Catholic Archdiocese did not get the joke when the song was first released in 1952. The organization wanted the song to be banned because it glorified adultery — they thought Mommy was really kissing Santa Claus.

“Do You Hear What I Hear?” 

This song has an old, liturgical feel to it, but it’s actually one of the newer entries in the holiday music canon. Gloria Shayne Baker and Noel Regney wrote it in 1962 during the Cuban Missile Crisis as a desperate plea for world peace.

“Up on the Housetop”

This jaunty tune from 1864 is believed to be the first Christmas song to mention our modern notion of Santa Claus. Songwriter Benjamin Hanby was inspired by the classic poem “A Visit from St. Nicholas,” as “Old St. Nick” is up on the housetop, about to head through the chimney.

“It’s the Most Wonderful Time of the Year”

It’s a delightful song, but one line seems a little out of tune — the lyric about people hanging out on Christmas telling “scary ghost stories.” Isn’t that more of a Halloween thing? Yes, and no. In the Victorian era of the 19th century and into the early 20th century, it was a common Christmas pastime to tell ghost stories on Christmas Eve. That’s part of the inspiration for the ghost-heavy A Christmas Carol by Charles Dickens. (So if you watch a movie version on Christmas Eve, you’re keeping the tradition alive.)

“Silent Night”

It’s a calm, gentle song, befitting its title, right? Wrong. When Franz Gruber wrote the music in Austria in 1818, he called for it to be played in 6/8 time. That’s a fast, sing-song rhythm — think Queen’s “We Are the Champions.”

“Silver Bells”

Songwriters Jay Livingston and Ray Evans called the first draft of their song “Tinkle Bell,” until Livingston’s wife pointed out that most people associate the word “tinkle” with going to the bathroom.