I was just a little tyke when "A Charlie Brown Christmas" special first came on television. As a kindergartener, I was old enough to enjoy the content, but too young to appreciate the significance of it being on network television.
Until then, the Biblical narrative of the birth of Christ never had been part of commercial television programming. But the immensely popular Peanuts comic strip had already broached the religious subject in newspapers throughout the country. "A Charlie Brown Christmas" special was the television version of the Charles Schultz strip, complete with the story of the birth of Christ, as told by the ever-wise Linus.
A recent Nuclearity podcast looks at how the special came to television, and includes interviews with a number of people whose lives were impacted by it.