It may be hard to imagine but A Charlie Brown Christmas first aired on CBS TV on a Thursday evening, December 9th in 1965.  It preempted The Munsters.

Filmed with almost no money, as evidenced by the flatness of the animation and the relatively poor soundtrack quality, A Charlie Brown Christmas was an instant success.  Much to the surprise of the CBS executives, who were less than enthusiastic about the program, both critics and audiences loved it.  Harriet Van Horne of the New York World-Telegram said in a 1965 review that, "Linus' reading of the story of the Nativity was, quite simply, the dramatic highlight of the season."

There were several reasons why the CBS executives were surprised by the program's success.  For one thing they didn't like the music.  They were convinced that the jazzy soundtrack as written and performed by Vince Guaraldi was completely wrong for the show.  Also, they didn't care for the children's voices.  The executives wanted to employ adults pretending to be kids to do the voice acting. 

The absence of a laugh-track, which was quite common for children's cartoons at the time, was another complaint, plus the execs weren't keen on having Linus recite the Nativity in such detail.  After viewing a final edit of the show, the executives are said to have been horrified, convinced they had produced a flop.

The original sponsor of the show was Coca-Cola, and purists might find it interesting to note that the show has never been aired in its original form since 1967.  The main titles saw Linus crashing into a Coca-Cola sign, which has since been cut.  When the gang try to knock cans over with snowballs you may recall that Linus can be seen knocking down a can with his ever-present blanket.  In the original production, the can was a can of Coke, but later showings changed the look of the can to something more generic. 

Also, have you ever noticed how the show comes to such an abrupt end while the gang is still singing?  This was because there was always a network voice-over at the end that spoke over the singing and wished all viewers a "Merry Christmas from the people in your town who bottle Coca-Cola."

Despite the fears of the executives, it is said that almost fifty percent of all television sets in America were tuned to A Charlie Brown Christmas on that December evening in 1965.  It went on to win an Emmy and a Peabody award.  Quite an achievement for a show that was almost never made.