“A Charlie Brown Christmas” has become almost as iconic now as the holiday it celebrates. The special celebrates its 50th year Monday night on WNEP/...

“A Charlie Brown Christmas” has become almost as iconic now as the holiday it celebrates.

The special celebrates its 50th year Monday night on WNEP/ABC, with both the animated program and a preceding star-studded celebration called “It’s Your 50th Christmas, Charlie Brown” beginning at 8 PM.

Here are a few little-known facts about the holiday special.

‘A Charlie Brown Christmas’ almost didn’t happen

Lee Mendelson, the executive producer for the special, said in 2006 that CBS network executives did not love it when it was first screened for them in 1965.

“They said, ‘We’ll play it once and that will be all. Good try,’ ” Mendelson told Pop Matters. He and director Bill Melendez “thought we had ruined Charlie Brown forever when it was done. We kind of agreed with the network. One of the animators stood up in the back of the room — he had had a couple of drinks — and he said, ‘It’s going to run for a hundred years,’ and then fell down. We all thought he was crazy, but he was more right than we were.”

The soundtrack is huge, but Charles Schulz was not a fan of jazz

The studio album of music from the special, composed by Vince Guaraldi and performed by his trio, has also become a staple for the holiday season.

It’s so popular that it was added to the Library of Congress’ National Recording Registry. “Christmastime is Here” helps set the tone for the holiday season, and who hasn’t danced to “Linus and Lucy” just like the characters do (albeit minus Schroeder on the piano)?

Ironically, “Peanuts” creator Charles Schulz was not into jazz, and according to “Schulz and Peanuts: A Biography,” he once told a reporter that he hated such music.

Some of the child actors weren’t actors at all

Melendez didn’t have to look far for some of the voices of the characters, casting kids from his neighborhood in Southern California.

He and Schulz wanted to use actual children as opposed to adults faking young voices. Charlie Brown, Linus and Lucy were portrayed by actual child actors, but the other voices were ordinary kids.

Some of the children were so young that they couldn’t read. In “A Charlie Brown Christmas: The Making of a Tradition,” Melendez recounts how he had to recite the script line by line for Christopher Shea, the young actor who voiced Linus.

Linus’ legendary speech almost wasn’t

Speaking of Linus van Pelt, his now-famous monologue about the true meaning of Christmas was almost cut.

Linus quotes the second chapter of the Gospel of Luke from the Bible. After reciting verses 8 to 14, Linus tells his friend, “That’s what Christmas is all about, Charlie Brown.”