To the casual observer, the Holy Roman Empire seems locked in time, continuing its almost feudal tradition even while every other part of Europe was consolidating into nations and empires. By the time Prussia conquered the rest of what we now call Germany, Britain and France and Spain had been (at least nominally) unified under single heads of state for the better part of a millennium.
What took so long? Why didn't Germany get consolidated alongside her neighbors into a single empire? And what kept the other major powers of Europe from gobbling the pieces of the Holy Roman Empire up amongst themselves?