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PODs of the Thirty Years War XXXVIII

By Alex Richards

The failed Swedish-Transylvanian siege of Brno as depicted by Hieronymus Benno Bayer

Having resolved the situation with Denmark to their satisfaction, Swedish interests now turned back to the Empire. Ferdinand III had used the Swedish manoeuvres in Jutland to make small advances in Silesia, but the larger hopes of trapping the Swedish army in the far north had floundered on the lack of supplies and inability to expel their garrisons from the towns of Mecklenburg. Nonetheless, hopes in Vienna were still strong that a decisive blow could be dealt in the north that would allow the negotiations now beginning in Westphalia to be conducted largely on Imperial terms. The year 1645 was to prove the limits of this with respect to Sweden.

Torstensson Marches South

While the unexpected disintegration of Gallas’s army in the closing stages of the Torstensson War created a significant opening for the Swedish army to advance, on the Imperial side there was a reluctance to acknowledge the reality of the strategic situation. While nobody expected total victory anymore; or even that a unified Imperial front against outside intervention could be achieved; it was still felt that the three pillars of Ferdinand’s opening negotiations- the retention of the 1635 settlement, achieving a better deal against Sweden and a separate peace with France- could be achieved. To that end, a widespread fundraising campaign for a new army was enacted, with the monasteries and the Emperor himself demonstrating their generosity and commitment by offering up church silver and some of the Crown Jewels to the effort. Once combined with the reserve army under Hatzfeldt and what could be begged from the armies of Bavaria and Saxony it meant by January 1645 that this gave the Imperial army 11,000 cavalry, 500 dragoons, 5,000 infantry and 26 guns gathered at Pilsen.

In opposition to this, Torstensson had a strike force comprising of 9,000 cavalry, 6,500 infantry and 60 guns, with a further 27,500 across the north of Germany. He advanced into Bohemia in the middle of January, hoping to act before the new Imperial army was ready to fight, aiming for Swedish occupied Olmütz and to expand the bridgehead in Moravia. Hatzfeldt had correctly surmised that these would be his intentions, but was unable to cut Torstensson off as it was unclear whether the Swedes would pass north or south of Prague, and thus when Torstensson crossed the frozen Moldau to the south of the city he was forced into a reactive position once more.

Hatzfeldt managed to intercept the Swedes on March 6th in the hills near Jankau, drawing up between a steep slope on his right and dense woodland on his left, with the Jankova stream, the town of Jankau and a network of ponds between himself and the Swedish positions. The Swedes made an initial move to secure Chapel Hill; an area of higher ground without which they would have been unable to safely pass through the ponds; at a time when Hatzfeldt was reconnoitring and had left Count Götz in charge with vague instructions to hold the hill. Götz, for reasons which remain unexplained, chose to abandon his highly defensible position and advance the entire left wing of the army across the obstacles that were between him and the Swedish army, only realising that he was unable to extract himself from the manoeuvre when the army got stuck in the dense woods.

Hatzfeldt brought the main army down to join Götz as a fierce firefight erupted to prevent the Swedes from advancing beyond the ponds, but despite overrunning two Swedish infantry brigades, the Swedish guns had been successfully dragged over the hard frozen ground and onto Chapel Hill and proceeded to disrupt the Imperial advance. In contrast the Imperial guns had become stuck in the mud of the woods and would end up being captured by the Swedes as they pushed to take the higher ground on the Imperial flank and compelled Hatzfeldt to retreat to the north.

Jankau could have ended here as a moderate victory for the Swedes which would have opened up the route to resupply Olmütz while leaving the Imperial forces largely in control of Bohemia. However, Hatzfeldt’s decision to fortify in place while waiting for nightfall to slip away from the battlefield troubled Torstensson – who had expected them to continue their retreat- and after a short rest to redeploy roughly perpendicular to the original front- and thus with the Jankova and the woods out of the picture- battle recommenced. Here again the battle could have had a radically different outcome- Werth’s Bavarian cavalry successfully routed their Swedish counterparts, pushed through to the rear and captured the Swedish baggage train and women- including Torstensson’s wife Beata de la Gardie. Even as the Bavarians advanced, however, the infantry in the Imperial centre were growing dispirited, and when the Swedes rallied, rescued the women and drove off the Bavarians it was followed soon afterwards by the collapse of Hatzfeldt’s centre- the remnants fighting until nightfall before escaping. For the loss of around 4-5,000 men, the Swedes had inflicted 5,000 casualties, captured 4,500 infantry and the Austrian guns, and effectively eliminated the Imperial army. A week later the Imperial army mustered a notional 36 regiments in Prague. The total number of troops and officers present numbered just shy of 2,700.

The Swedes in Austria

The Battle of Jankau was an unmitigated disaster for Ferdinand III. Götz was among the senior officers killed, Hatzfeldt had been captured in the rout, the veteran Bavarian cavalry had been essentially wiped out and Bohemia was essentially undefended. Torstensson swiftly took advantage of the situation, resupplying Olmütz, sweeping across southern Moravia and arriving outside the gates of Vienna with 16,000 men on April 9th. To add to the sense of déjà-vu for those who remembered Count Thurn’s siege, the Transylvanians under Prince György I Rákóczi were on the advance in Hungary, raising the prospect of a joint siege- though the now largely Catholic Hungarian nobility proved a more effective block than 25 years previously.

Unlike the Battle of White Mountain however, the military collapse was not followed by a political one. Even as the people of Vienna rallied to form up defensive militias, Torstensson found himself unable to cross the Danube and the Transylvanians were largely uncooperative when they arrived on the scene- mostly due to Torstensson’s lack of funds for wages. Instead he turned north and attempted to take Brünn- now Brno- only to find that the fortress managed to hold out over a three-month siege, much to the relief of Ferdinand III. Meanwhile Transylvania’s backers in the Ottoman Empire became embroiled in a war with Venice, and they accepted a peace deal in August for the Upper Hungarian counties granted to Bethen.

With the Transylvanians out of the picture, Torstensson was forced to abandon the siege of Brünn on August 19th, making a second attempt on Vienna. In increasingly poor health, however, he abandoned this in October, retreating to Thuringia and handing command over to Wrangel. He had been reduced to 10,000 men, and the remaining Swedish garrisons in Bohemia were expelled by February 1646.

Ferdinand III had proven more resilient than many in his position, but the Swedish advance had prevented him from acting outside of the Habsburg heartlands for most of the year. In the meantime, the French had been on the attack.


Alex Richards is the author of Tippecanoe and Wallace Too, published by SLP


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