Christmas-less Historical Fiction Fantasy

I remember hearing about a book/ series that examined history... as if prior historical events had different outcomes (eg: Allies lost WWII, Spanish Armada beat the English, etc.)

What would a book be like about 2014... if Jesus had never been born?

It's probably so massive a historical change that it'd be all but impossible... (Would science/ technology have developed as far? Under what conditions? What religions would still be existing? Not Islam. Germanic? Celtic? Which belief systems would rule?)