Here is a link to a wonderful video showing how the political map of Europe has evolved from 1000 AD to the present.

There is no date counter, but the progress bar at the bottom of the video will give you a good sense of the date at any point. 

Thanks to Robert Graboyes for pointing me to this.

Robert also recommends this (unfortunately not free) amazing video of the shifting battle lines during the Civil War. Here is the free trailer.