Well that was certainly informative, guess I went a little far back. I would also be interested in how the political situation influenced the Thirty Years War. It devastated Germany and I've always felt Roman dreams of an empire had a lot to do with the devastation. Your thoughts...
I am quite sure I can follow you. The Romans - the original ones, from Rome, who started this "Roman Empire" thing - had, very basically spoken, one major reason for building their empire: loot. All of the Roman foreign politics - in latter times less than in the early era - was fundamentally city internal power politics. Fighting your neighbor brought you loot and fame, which raised your status and gave you power. Conquering your neighbor lead to defending your new conquests... and brought new neighbors. It's interesting to see that the Roman expansion stopped where new conquest meant more costs than gain, either due to not enough gain (Germania and the skytian steppes, or saharan Africa) or too much expense (like fighting against the Parthians or Persians).
With the times, the basic stability and the general shift away from city-Rome as a sole focus of power, the approach changed. Another factor was the advent and spread of Christianity, and its views on eschatology. The Roman Empire was considered the pinacle of civilization, the "last empire" before the end-times... something good and great in itself.
The people of the Great Migration never meant or wanted to
destory the Roman Empire... they wanted in on the business. The Roman Empire at this time had too many internal problems to be able to integrate them... had the situation been a little better for the Romans, all these germanic kingdoms would have sooner or later just been soaked up, and their population become "Romans"... just like the people of Gaul, Spain, Africa.
And the "Roman Empire" never fell. For centuries, there had been political divisions. The Empire might have lost control over some territory... even its original city. But the "Roman Empire" had long ago been seperated from the city of Rome. There was a "Roman Emperor", there was an Empire... that the West wasn't controlled by it was just a minor setback in the overall system of things.
So the
idea of the Roman Empire had never ceased. The coronation of Charlemagne in 800 was just the continuation of a temporarily lapsed office. In the mind of the people, it was the same Empire, the same office... just after a period of vacancy.
But this was the Christian Roman Empire. One of its main attributes was that it was THE Christian Empire. It was the secular realm
meant to protect Christianity and the Church until the End. This mean the idea of the "Roman Empire" was universal.
Charlemagne's empire didn't survive. It couldn't survive the dichotomy between the "universal realm" and the familiy-oriented form of germanic rulership. That there should only be one (western)-roman emperor who should have the allegiance of the other frankish kings didn't hold up in reality. The family feuding of the Karolingians quickly reduced the "Emperor" to an unimportant prince in Italy.
It took a dominating leader figure to reestablish. There are a number of reasons why Otto the Great, King of Germany reached for Italy and the (again lapsed) imperial crown... but without doubt at the time he tried, he
was the most powerful ruler of any of the Karolingian successor states, and the Church saw a powerful protector in him. And even though he never tried to expand his overlordship into a formal rulership over the other kingdoms, France and Burgundy, he definitly saw his rule as universal, and as the (secular) head of (western) Christianity.
So the idea of the "Empire"... the Roman dream... continued, and it continued to be inseperably connected with Italy. That was the problem that continued to trouble the Kingdom of Germany.
Her kings were meant to be Roman Emperors. They were meant to be universal rulers, and they were meant to rule Italy and protect the pope in Rome. The recurring need to excert power in Italy meant that the kings had to delegate power in Germany.
While in France, the monarchy managed to regain the power it had lost to the nobility, mainly in the later wars against England, and the Norman conquest of England established and formalized a centralized monarchy, in Germany it was the division of power between king, electors and nobility that became fixed.
And after all this long-winded explanation, and after a lot of events left for other questions, we come to the Thirty-Years-War.
The "Holy Roman Empire" had lost a lot of its universality at that point, especially after the discover of the Americas had shifted the focus of power to the Atlantic states: Portugal, Spain, France and England. The division of power between the Emperor and the nobles had become a legalized fixture. Each Emperor could only excert as much power as his personality and personal lands could afford.
And there was a new division of power: the split in the Christian church. During the last century, Germany had found a workable solution that had prevented a major civil war like the one in France. There had been a treaty, the "Augsburger Religionsfriede", which established Protestantism as an accepted religion in Germany, and guaranteed both confessions their status. But it was complicated, couldn't solve many details, couldn't solve the basic question of "Christian unity" at all... and it didn't foresee the future complications.
One of those was the rise of a
third confession: the calvinistic "reformed" confession. This new church and the rulers and people who followed it were not part of the Augsburgian treaty. There very existence threatened the status quo. It made all sides more wary towards each other.
That's the basic situation before 1618. Catholic princes and the emperor, set on keeping what they still had, and trying to regain what the catholic faith had lost. Protestant princes trying to keep what they had gained and defend their position against recatholisation. Calvinist princes trying to gain status for themselves, be an accepted part of the system. And between all these, the people of these fiefdoms, trying to establish their status, their power, their religion.
War started when the catholic king of Bohemia - who was also the emperor - tried to recatholizise this land, over the wishes of her nobility. They rebelled and chose a calvinist prince as their new king. This war was over rather quickly, the calvinist lost, and this could have been the end of this thing. But rather it escalated. Every side now saw this as a chance to gain for power for their side, which induced others to defend themselves against the other. Foreign powers took the opportunity to futher their own goals on the expense of Germany. It became a big huge free for all, take what you can grab.