By Alex RIchards
While seeing initial successes, by 1636 the French position in Alsace had stalled and she was facing renewed attacks on Lorraine in tandem with attacks from the Spanish Netherlands. While for the moment her territorial gains in Lorraine and Alsace had not been undone, it was clear to all involved that the situation was precarious and would require significant investment of resources by the French to resolve in their favour. Despite this, they had been unambiguously successful in unifying the forces opposed to the Emperor in the region behind them- Bernhard of Saxe-Weimar had been convinced to defect, together with the vast majority of the Swedish garrisons that had been established in Alsace. The next few years would be dominated by Richelieu’s perceived need to secure Alsace in order to ensure control over the Duchy of Lorraine, and the desire to push the Empire onto the back front.
Forcing the Rhine
With the fall of Mainz France’s most significant forward position in the Empire was the Ehrenbreitstein fortress in Koblenz, which they had occupied since 1632 when Archbishop-Elector Philipp Christoph von Sötern had invited them to oust the Spanish-Imperial troops that had ejected him from his electorate. While the Elector had been imprisoned since the Spanish captured Trier in 1635, the Ehrenbreitstein was a tougher prospect to capture and had been subject to a siege since August 1635. On May 8th 1637 it finally fell to the Imperial forces cutting France off from Hesse-Kassel for the time being.
Richelieu’s response was to send the Seigneur du Hallier with 5,800 troops to reinforce Bernhard in Alsace, who promptly turned south to assist with the ongoing attempt to conquer the Spanish County of Burgundy (now known as the Franche-Comté), before returning to Alsace in July with the news that Gallas had moved to assist the Saxons in the east. With the Free City of Strasbourg refusing to allow either side to use her bridge- the only one on this stretch of the Rhine- Bernhard attempted to cross at Rheinau on August 6th 1637, but only a month later was forced back by Werth and retreated south to the Prince-Bishopric of Basel, despite the protestations of her allies in the Swiss Confederation.
The following year, however, gave Bernhard several distinct advantages. He had been joined by the Duc de Rohan who had managed to escape from the Spanish advances in the Valtellina; he was close to the stretch of the Rhine stretching from Basel to Lake Constance which had more crossing points than the wider river further north; and his main opponent in the garrisons to the north was the under-resourced Frederico Duke di Savelli, a commander of little in the way of competence even when not commanding an army mostly made up of understrength regiments, lacking supplies, starving and where the men were going without pay while the expensively maintained officers disproportionately survived the military clashes, though many of these were themselves ill. Only the 800 me under Colonel Reinach in Breisgau represented a significant threat as an individual unit. Crucially, Bernhard also had an extensive spy network in Swabia which meant he was well aware of how poor the Imperial position really was.
February 1638 brought two key developments for Bernhard. First secret negotiations conducted with Major Widerhold, the commander of the Hohentwiel Fortress, secured the open alliance of the only garrison still holding out against the Empereor in Swabia, despite his nominal liege Duke Eberhard III of Württemberg ordering him to surrender in 1637 in return for the Emperor recognising his position as Duke.
The Battles of Rheinfelden
Meanwhile Bernhard was attempting to force the bridge at Rheinfelden, whose garrison had been holding out since January 28th. While he had been able to take the bridge at Laufenburg and the ferry at Beuggen, Rheinfelden represented both the best bridge and a garrison that could not be allowed to risk blocking his supply chains. His army at this point totalled only 6,000 men due to the losses from the previous year’s campaign.
Werth meanwhile had recognised the threat this posed and force marched to relieve Rheinfelden, gathering Savelli, 2,600 infantry and 4,500 cavalry from the garrisons north of the river. He arrived on February 28th 1638 near the Beuggen ferry with no artillery and little ammunition due to his forced march through mountainous terrain.
Bernhard initially had the upper hand, managing to move his own cavalry to face the arriving troops on the northern bank and charged the Bavarian cavalry before it could properly organise. However, with only half his army across the river Savelli arrived and managed to turn Bernhard’s flank while he was advancing, capturing the ferry and forcing Bernhard to retreat towards Bad Säckingen. While only losing 150 men and three canons, Bernhard’s casualties included a mortally wounded Duc de Rohan, and the Imperial forces concluded that the haste of his retreat meant the army was now scattering in a general rout.
This, while understandable given the forced march and short rations their troops had been subjected to, was to prove their undoing. Bernhard regrouped at Laufenburg, where he was joined by the rest of the army on March 2nd. He then advanced back to Beuggen, collecting the three cannons he’d been forced to abandon in his retreat, and surprised the Imperial troops before they could fully prepare for the forthcoming attack, starting off with three rounds of artillery before encircling the Imperial army with the cavalry and comprehensively defeating them. Werth and Savelli were both captured, and proceeded to blame each other for the defeat, and Bernhard captured Rheinfelden three weeks later.
The importance of Rheinfelden to French strategy is difficult to understate. Without the victory here, securing a supply line across the Rhine and offering the opportunity to move the focus of the conflict into Swabia and away from Alsace, it is likely that the French position on the Upper Rhine would have remained distinctly on the defensive, putting more pressure on the need to advance in Flanders and the Moselle valley. In addition the removal of the competent Werth from the equation for the time being- he would remain imprisoned by the French until 1642- was a significant loss to the Imperial forces. The loss, from either death or capture, of Bernhard would also have likely prevented the historic successes of the later 1638 campaign even if victory had been achieved. In this the question is not necessarily one of talent- Bernhard was noted for his daring but it would not have been impossible for others to achieve the same things- but the loss of momentum while a new commander was appointed would have pushed any campaign into 1639 or beyond, potentially allowing Imperial reinforcements to arrive.
As was, the road was now open for Bernhard to advance into the Austrian Breisgau. It was to be his last, and arguably greatest, campaign.
Alex Richards is the author of Tippecanoe and Wallace Too, published by SLP