Peace on Earth

So, I guess it's time to spill the beans. I am writing a mini-christmas-musical, believe it or not. As surprising as this may be to you, it actually seems to be happening. "Peace on Earth" will perhaps not be as christmassy as the title makes it out to be, but a it bears a message relevant to christmas nonetheless. What was this Peace on Earth the angels sang about, is it still here? If so, where?