The Elector of Mainz, who had been among the foremost critics of Wallenstein’s growing power, convened a meeting of the Electors (Kurfürstentag) at Regensburg (Ratisbon) in July, 1630. Although the meeting was in form a mere meeting of the Imperial Electors, the tensions within and without the Empire led to the meeting becoming an international conference.
Because of the situation within and without the Empire, the politics of the Diet became correspondingly complex.
Emperor Ferdinand II wanted his son Archduke Ferdinand elected “King of the Romans”—heir apparent to the Imperial throne. He was thus willing to entertain the complaints of the Electors.
He also wanted it made clear that the Frederick, the outlawed Elector Palatine, would not receive pardon.
Further, at the insistence of the Spanish Habsburgs, the Emperor was to try to gain Electoral approval for a war against the Dutch.
Maximilian I of Bavaria and the other Catholic electors were frightened by the size of the Imperial army, which had been raised without so much as a by-your-leave from the Electors.
The Emperor’s generalissimo, Wallenstein, had pushed the Catholic League armies out of prime winter quarters and forced them back into the territories of the Catholic rulers. The Catholic princes were thus anxious to see the Imperial army reduced in size and command taken from Wallenstein.
The Protestant Electors, irate over the Edict of Restitution, refused to attend the Diet in person. Instead, they dispatched ambassadors and convened a protest meeting at Annaburg Saxony, from which they issued fulminations against the Edict.
In addition to their hatred of the Edict, the Protestant Electors shared their Catholic brethren’s fear of the Imperial army and Wallenstein.
The French and Spanish sent ambassadors to the Diet. Each of them had goals which they expected the Emperor or Electors to be able to advance. Further, each was willing to try to settle the War of Mantuan Succession then raging in northern Italy.
The French were frightened by the participation of Imperial troops in the Spaniard’s wars. Imperial forces had taken part in the 1629 campaigns against the Dutch, and were currently in the field in northern Italy assisting the Spanish in the Mantuan war. The French sought to make sure that the Electors succeeded in reducing the power of Imperial arms in order to prevent further assistance to their Spanish enemies.
The Spanish sought Imperial assistance in their continuing war against the Dutch. The Low Countries campaign of 1629, which the Spanish had waged with the assistance of troops seconded them by Wallenstein, had been disastrous for Spanish arms.
Faithful to his Spanish cousins (whose subsidies kept him in power), the Emperor requested the Electors declare war against the Dutch, on the grounds they had occupied various places in Germany. The Electors noted that the Spanish were equally guilty of grabbing German lands and refused to involve themselves in the interminable wars of the Low Countries. Ferdinand II was forced to drop the point.
The Electors, Protestant and Catholic alike, wanted Wallenstein dismissed and the Imperial army reduced to a third its current size. Although he knew of the current of feeling against him, Wallenstein lurked in princely splendor at Memmigen making no move to come to nearby Regensburg and defend himself.
The Emperor was willing to give up his army and his general in order to avoid a break with the Catholic electors.
On 13 August 1630, Wallenstein was removed from his command. The general retired quietly to his Bohemian estates. In truth, the financial strain of maintaining an army for the penurious Austrian Habsburgs was too much for any man. Shortly after the dismissal, de Witt, Wallenstein’s financier, was a bankrupt suicide.
With Wallenstein gone, the question then became who was to replace him as Imperial commander-in-chief. The Catholic electors wanted Maximilian to take command of the armies, as a check on Habsburg ambition. The Spanish (who were in large part paying for the army) rejected him for the same reason. In the end, Maximilian was obliged to withdraw his name from consideration.
In the end the command of the Emperor was entrusted to that most faithful of Catholic generals, Tilly. The old warrior also continued in command of Maximilian’s Catholic League as well. The Imperial forces themselves were to be reduced to 39,000 men under arms and the League forces to 20,000.
The Emperor was willing to reduce his army because he believed that his forces in Northern Italy would no longer be needed. Habsburg arms were prospering in northern Italy: in July, the Spanish and Imperial armies had taken Mantua in a brutal sack from which the place has yet to recover.
On 13 October 1630 the French ambassadors, panicked by these reversals, agreed to peace.
The terms were advantageous to French interests in Italy, in that the rights of the French candidate for the Mantuan duchy were confirmed, subject to indemnifications in favor of the Duke of Savoy and another northern Italian duke. Indeed Olivares, the Spanish first minister, thought the terms so inimical to Spanish interests as to be little better than a surrender.
However, the Regensburg treaty would have prevented the French from pursuing a more active policy in Germany as its terms included an agreement that the French would not meddle in the affairs of the Empire
Louis XIII of France refused to accept the peace made in his name. Thus the Emperor found himself with diminished forces and a war still to be fought. The Italian peace was not made until the Treaty of Cherasco on 19 June 1631 and the forces diverted south of the Alps were to be sorely missed in the early months of the Swedish invasion.
Despite the Emperor’s concessions, the angry Electors still refused to make Archduke Ferdinand King of the Romans. In September, the election was uniformly rejected by Catholic and Protestant alike and the Emperor finally closed the fruitless Diet on 12 November 1630.
While the Emperor, the Electors and the ambassadors were engaged in their political maneuvers, an event had occurred that would be the ruin of all their calculations: the Swedes had arrived in Pomerania.
On 26 June 1630 a great Swedish fleet appeared off the shores of the Pomeranian island of Usedom at Peenemünde. It landed a small, seasoned army of Swedish veterans of Gustavus Adolphus’s endless Baltic wars.
The invader moved swiftly inland to Stettin, capital of Pomerania. On 10 July 1630, a treaty was signed with the Duke of Pomerania and the place was occupied by the Swedes.
The Swedes then attacked the Imperial forces on each side of the river Oder. Gustavus intended to link his bases in Poland with his field army along the Oder and his garrison in Stralsund.
With the fall of Wolgast in August 1630, Gustavus was able to effectively control the coast from the Oder west to Stralsund, although Savelli and the Imperial forces retained Greifswald, midway between the two points.
To the east of the river the Swedes began to clear the coast between Poland and the Oder, with forces under Horn besieging Kolberg.
In September 1630, Gustavus felt strong enough to try a diversionary attack into Mecklenburg. There he attempted to rouse the populace to restore the deposed Dukes of Mecklenburg. The Mecklenburgers, contented with the excellent government the usurper Wallenstein had given them, did not respond.
Despite the diversions against Mecklenburg, the focus of the Swedish attacks remained the valley of the River Oder.
The Imperial forces had concentrated at the river city of Garz and the associated fortress of Greifenhagen only twenty miles south of the Swedish base at Stettin. From there they were able to mount raids into Swedish-held territory or detach forces to relieve Kolberg (as they did, without success, in November, 1630).
Gustavus determined to concentrate his forces and destroy this impediment to his expansion.
In a daring storm of a fortified positions, Gustavus took the Greifenhagen on 24 December, 1630. On 25 December, 1630 Schaumberg and the remnants of the Imperial forces retreated upstream, passing through the nominally neutral Brandenburg fortress of Küstrin, and fleeing finally to Frankfort-am-der-Oder and Landsburg on the Warthe.
When his forces landed, Gustavus was entirely without support within the Empire. He sought alliance among those who had pre-existing quarrels with the Empire, Hesse-Cassel and Magdeburg, and with the dispossessed, the Dukes of Mecklenburg and the Elector Palatine.
He was also willing to acquire allies by force, as the Duke of Pomerania was to discover.
Upon arrival of the Swedes on 10 July 1630, the aged Bogislav XIV of Pomerania, was forced into Swedish alliance at gunpoint. The aged Duke begged to be left neutral, but Gustavus refused.
Duke Bogislav XIV of Pomerania was old and childless. Elector Georg-Wilhelm of Brandenburg, was, by ancient family compact, the heir-apparent.
Under terms of the Suedo-Pomeranian treaty, Brandenburg was required to either fall in line with Sweden or face the loss of its Pomeranian expectations.
On 1 August 1630, the city of Magdeburg, which had been re-Catholicized as a result of the Edict of Restitution, allied itself with Gustavus.
The city had risen in rebellion against Imperial commissioners who were attempting to re-Catholicize the place. The rebels returned Christian-Wilhelm, the Protestant Administrator, to power.
Christian-Wilhelm assembled troops and roused the Bishopric of Halberstadt against the Emperor. However, von Pappenheim, Tilly’s dashing cavalry general, made quick work of the rebels in the field. Magdeburg was thereupon invested by the Imperial forces.
On 29 October 1630, Gustavus sent a small garrison under the command of von Falkenburg to Magdeburg. Von Falkenburg’s instructions were to resist the Imperial siege for three months until Gustavus could arrive.
Gustavus sought another ally in the Calvinist Landgrave of Hesse-Cassel. Wilhelm had found himself deprived of the lands in Marburg he had conquered from his Lutheran cousin, Georg of Hesse-Darmstadt.
The parties agreed in November, 1630 to the “Contingent Convention,” a treaty under which Hesse-Cassel and Sweden bound themselves to an offensive alliance against the Emperor. Wilhelm in the end refused to ratify it. The terms of the treaty, which made Hesse-Cassel a tributary of Sweden for the duration of the war, were just too onerous to be accepted.
The French had been instrumental in the Swedish irruption into the Empire: it was they who had procured the peace in Poland which allowed the Swedes to war in Germany. Now, impressed by Gustavus’s initial success, Richelieu sent an envoy to the Swede’s winter headquarters of Bärwalde to negotiate an alliance. This was ultimately agreed 13 January 1631.
The Treaty of Bärwalde required the French to subsidize the Swedish forces in the amount of 400,000 Reichsthaler annually. In return, the Swedes were to maintain a force in Germany. The Swedes were not to attack the forces of the Catholic League (so long as they remained neutral), nor were the Swedes to interfere with Catholic worship where established. The Treaty was to remain in force until 3 March 1636: clearly, neither the French nor Swedes were expecting a swift end to Germany’s troubles.
Even while they were negotiating their arrangement with the Swedes, the tireless French diplomats were coming to an arrangement with Maximilian I of Bavaria, the head of the Catholic League.
The Treaty of Fontainbleu was signed on 30 May, 1631. Under this secret compact, the French and Bavarians were to be bound by a defensive alliance. The French agreed to recognize Maximilian’s claims to the Palatinate and its Electoral title. Maximilian also negotiated an opportunity to change sides, since his duties to his French allies were made expressly subject to his obligations to the Emperor.