Jankau left the Imperial arms in the East shattered. Vienna lay open to the the conquering Swedes, whose armies, at April’s end 1645, approached within 30 miles of the place. Ferdinand III hurriedly fled to Grätz.
However, rather than pursuing his attack on the Habsburg capital, Torstensson determined to secure Moravia by the conquest of the city of Brno (Brünn). The place resisted valiantly for more than five months, giving the Imperials in Austria time to regroup.
The breaking of the Imperial forces at Jankau provided Rákóczy too tempting an opportunity to abjure. In April, 1645, he re-opened hostilities with the Emperor.
Aided by Swedish troops, Rákóczy took Tyrnau and besieged Bratislava (Pressburg).
These actions ran against orders of Rákóczy’s master, the Turkish Sultan. The exasperated Sultan was forced, to recall Rákóczy to his duty by bloodcurdling threats. Peace between Transylvania and the Emperor was accordingly re-made on 8 August, 1645.
The siege of Brno (Brünn) proving fruitless, in August, 1645 Torstensson turned his armies south once more. However, the Danube was held in strength by Leopold Wilhelm. In the end Torstensson withdrew his main field army to Bohemia. The threat to Vienna was over, and the advantages promised by Jankau squandered.
The French, seeing in the chaos left by Jankau an opportunity for themselves, advanced against Bavaria.
Turenne, afflicted by overconfidence, dispersed his troops in the area of Mergentheim. The Imperial Bavarian army under Mercy and Werth took the French by surprise. On 5 May, 1645, Turenne was handed a crushing defeat in which his army of 10,000 was reduced to a fleeing column of 1,500 cavalry.
Pursued by the victorious Mercy, Turenne fell back on Hesse-Cassel. There he hoped to recruit aid from Amalie-Elisabeth of Hesse-Cassel and Königsmarck’s Swedish army.
Reinforced in the first instance by the Hessians and Swedes, and later by a force under d’Enghien, the French turned south to meet the advancing Bavarians.
Despite Königsmarck’s detaching himself from the Franco-Hessian armies, the Bavarians were still considerably outnumbered. Nonetheless, they determined to give battle to the French at Alerheim, near Nördlingen.
There, on 3 August, 1645, the Bavarians were driven from the field in a bloody battle that cost the life of the Bavarian general Mercy. The conflict left the French too weakened to follow up on their advantage, although they did occupy Nördlingen.
Shortly after second Nördlingen, Maximilian opened negotiations with France for a separate peace. It appeared that the long-time goal of French policy, to thrash Maximilian into deserting his Emperor, might soon be achieved.
Königsmarck, after detaching his army from those of the French and Hessians, carried out a campaign of terror throughout the defenseless Electorate of Saxony.
This finally proved all too much for Johann-Georg of Saxony. On 31 August, 1645, he entered into a six-months’ armistice with the Swedes under which they were to have right of free passage through the Electorate, as well as support in kind and in cash.
This armistice was later renewed on 14 April, 1646 by the Peace of Eilenberg, which was to remain in effect until war’s end. Saxony was out of the war.
Exhilarated by her troops’ part in the victory at Second Nördlingen, Amalie-Elisabeth determined to attack Hesse-Darmstadt and reclaim the Marburg inheritance and indeed take all of Hesse-Darmstadt in the bargain.
After considerable to-ing and fro-ing about the instructions given the Spanish ambassadors and the issuance in March, 1645 of a list of demands so vague as to be worthless, the French ambassadors at Westphalia finally issued their first concrete demands on 11 June, 1645, in conjunction with their Swedish allies.
Both France and Sweden insisted that the state of the Empire be restored to that of 1618, with a general amnesty issued and lands returned.
The coherence of the Empire (such as it was) was to be decisively weakened; all matters of war, peace and taxation were to be referred to the Diet, which would have to act unanimously or not at all. The estates of the Empire were also to have free reign to enter into alliances among themselves and with foreign powers.
France, Sweden and Hesse-Cassel were all to receive recompense for their troubles. The nature of this compensation remained unspecified.
The Swedish proposals added a demand for recognition of the Calvinists and required amnesty be extended to the Habsburg ancestral domains as well as the Empire.
In the fall of 1645, Ferdinand III officially rejected these claims. His own counterproposals, put forth on 25 September, 1645, were nothing more than a restatement of the Peace of Prague.
The Emperor dispatched his closest adviser, Trautmansdorff, to carry on the negotations. From Trautmansdorff’s arrival on 29 November, 1645, the negotiations began in true earnest.
In December, 1645, Torstensson, who had long been in poor health, resigned his command. He was replaced by Wrangel.
On 7 January, 1646, the Swedes put forth their demands for territorial indemnification. These were not unambitious: Pomerania, Kammin, Wismar, the Bishoprics of Bremen and Verden and a slice of Lusatia.
A few days later, on 11 January, 1646, it was the turn of the French to state what territorial gains they required as the price of peace. They demanded Upper and Lower Alsace, Breisgau, Sundgau and the fortress of Breisach, as well as garrisoning rights in Phillipsburg.
On 29 May, 1646, the Habsburgs finally conceded their rights over Upper and Lower Alsace. Phillipsburg was conceded on 31 August, 1646. A preliminary treaty between the Emperor and France was then signed on 13 September, 1646.
The exact nature of the concession was unclear. If it was merely the Habsburgs rights in the territory, these were very limited; if the sovereignty was conceded, the French gain was rather more.
The language agreed tried to have it both ways; in one tortured sentence, sovereignty was conceded, limited by the rights possessed by the various Alsatian cities and principalities and then granted again in the most absolute form. The parties knew the provision was incoherent, but would do no better.
The Imperial armies, aided by forces seconded by Bavaria, were able to outnumber Wrangel’s forces in Bohemia. The Swedes fell back, pursued by Leopold-Wilhelm and the Imperial forces.
The Swedes moved to northwestern Germany, where they captured Paderborn. They then joined with Amalie-Elisabeth’s army, which was still engaged in hostilities with Hesse-Darmstadt.
The Swedes were followed by Leopold-Wilhelm’s Imperial forces. Despite the fact that they outnumbered the Suedo-Hessian force the Imperials entrenched themselves south of the combined army rather than attacking.
Although the French were supposed to join the Swedes for the 1646 campaigning season, Turenne’s army had been kept inactive. Mazarin feared that an attack on the Imperial forces would disrupt his negotiations with Maximilian I of Bavaria.
Finally Turenne was granted permission to join the Swedes. He struck north, skirting the Imperial forces by a forced march of 14 days through the hostile territories of the Elector of Cologne. He joined Wrangel on 10 August, 1646.
On 14 August, 1646, the French and Swedes turned the flanks of Leopold-Wilhelm’s army and proceeded south. The Imperials were cut off from their bases in Bavaria. Leopold-Wilhelm tried to lure Turenne and Wrangel back by attacking Hesse-Cassel. The French and Swedes, convinced that a threat to Bavaria would end these attacks, would not be lured.
Instead, the Suedo-French force moved through Swabia and crossed the River Lech at Rain, as Gustavus had done years before.
Importuned by Maximilian I, on 4 September, 1646 Leopold-Wilhelm soon set off in pursuit of the Franco-Swedish force. But he was too late.
All of Bavaria save Munich and the fortress of Ingoldstadt had fallen to the invaders and was being systematically ravaged.
Maximilian had had enough. On 15 March, 1647, the Treaty of Ulm was signed between the Swedes and French on the one hand and Bavaria, Hesse-Darmstadt , the Swabian and Franconian Circles and the Elector of Cologne on the other. This resulted in a cessation of hostilities among all the parties.
The French and Swedes received garrison rights over various Bavarian cities to try to guarantee Maximilian’s good behavior.