See, I guess I should explain this one. (WARNING: POSSIBLE SPOILERS!)
In the anime/manga series Axis Powers Hetalia, there are "ChibiItalia" chapters focusing on a younger Italy. And one of the characters in it goes by the name Holy Roman Empire, who eventually befriends Chibitalia before having to leave... and never returns. Fast forward several years later, and a grown-up Italy is (rather reluctantly) joined by the character of Germany.
A commonly-held theory is that Germany really is a grown-up Holy Roman Empire... he just can't remember it. And since the characters each represent a different country, this apparently makes since from a historical standpoint. (Also, if you look at pictures of Germany and the Holy Roman Empire, don't they look an awful lot alike?
Only time will tell if this is really the truth or not. Until then, I'll just have to cross my fingers...
Axis Powers Hetalia @ Hidekaz Himaruya