By Alex Richards
With the defeat of the French at the Battle of Tuttlingen, the frontiers of the war in Swabia had returned to the same positions as they had been in at the death of Bernhard of Saxe-Weimar 4 years earlier. Yet little more than 3 years later the Bavarian army had been reduced to such a state that the Electorate was overrun in a matter of months. The reasons for this dramatic reversal of fortunes lay in the Swabian campaign of Louis de Bourbon, Duc de Enghien.
The Battle of Freiburg
With the destruction of the old Bernhardine army at Tuttlingen, the Bavarians under Franz von Mercy were for the first time in many years at a distinct advantage in troop numbers in Swabian theatre- their 19,450 men being twice the size of the hastily rebuilt French Army of the Rhine. As such, they went on the offensive in Spring 1644, taking Überlingen on May 10th and then attacking the Hohentwiel. While he was repulsed from that fortress and forced to leave 1,000 men to blockade the garrison, his continued advance meant that the French Marshall Henri de la Tour d’Auvergne, Viscomte de Turenne, was forced to abandon his own ongoing advance along the Rhine towards Hohentwiel, turn around and return to defend Alsace. Meanwhile Duke Charles of Lorraine took the advance as another opportunity to attempt to regain his homeland, breaking off negotiations and raiding into the Duchy. Mercy’s advance culminated on July 29th with the surrender of Freiburg after a short bombardment, the last significant town before Breisach itself and the French headquarters there.
In the meantime, however, d’Enghien had been directed to the area, marching rapidly from his position in Champagne and bringing a further 4,000 cavalry and 6,000 infantry to the Swabian theatre. Arriving just too late to relieve Freiburg, he linked up with Turenne nearby to create a force of 11,000 men, 9,000 horse and 37 guns, and immediately called for an attack to force Mercy back over the mountains of the Black Forest.
The war council on August 3rd represents a perfect summation of the differences in tactics and personality of the two men who were, arguably, France’s two greatest Generals of era- d’Enghien’s daring and tendency to try and use a ferocious attack to punch his way through defences contrasting with Turenne’s more cautious, considered approach. Freiburg, positioned at the western end of a deep valley heading into the mountains towards a pass leading to Tuttlingen, was already well defended by geography alone. To the north of the western approach was a narrow stream flanking the southern edge of the Mooswald Forest. To the south, the steep, wooded Schönberg hill effectively blocked manoeuvres. Mercy had constructed a series of fortifications on the lower flanks of the hill defended by 5 regiments of infantry, and positioned the rest of the army behind further fortifications on the northern side of the stream, with some 350 men positioned in Freiburg itself. With 8,200 cavalry, 8,600 infantry and 20 guns his army was now slightly smaller than the French force, but they had the distinct advantage in positioning.
Faced with this, Turenne recommended the strategy that would come to be the standard method in the later 17th Century, moving north before advancing across the Black Forest so as to threaten Mercy’s lines of communication into Württemberg, thus forcing the Bavarians to retreat. D’Enghien however insisted on making a frontal assault against the Bavarian defences, consenting only to allow Turenne to make an advance down the valley separating the Schönberg from the Black Forest proper so as to strike the Bavarian flank. Mercy was to prove their equal on both fronts however.
Eager to resolve the battle by the end of the day, d’Enghien ordered to attacks to begin at 5PM, leaving the French with only 3 hours of daylight. In the event Turenne would be 45 minutes early in his attack, despite the use of synchronised clocks, and had been spotted on his approach by Bavarian scouts on the top of the Schönberg. D’Enghien’s attack was both the most straightforward and the most bloody, loosing hundreds in two waves of attacks on the redoubts on the hill before the Marshall himself led the attack on the third wave. His victory here probably owed more to the Bavarians having run out of ammunition over the first two waves than it did to his presence at the front helping to stiffen the resolve of his own men, and his 1,200 casualties were twice the Bavarian losses, and represented a third of his own troops.
On the flank meanwhile Mercy had constructed 5 lines of entrenchments across the valley Turenne was advancing down, and then positioned 4 regiments to block his advance. Unable to bring his larger numbers of troops to bear in the narrow valley, Turenne was repulsed, having lost 1,600 men to the Bavarians 400-odd. Mercy however retreated rather than risk being cut off if an attack managed to make it through the valley, and positioned his troops on the Schlierberg ridge further up the valley. Between the French exhaustion and the rain that had turned the valley floor to mud, the Bavarians were given a full day to entrench themselves, now occupying the high ground between the river and the steep slopes of the mountains.
The French now had no choice other than to make another frontal assault if they were to take the field, with d’Enghien identifying the Wohnhalde- the highest point of the ridge tucked against the mountains and defended by 7 Bavarian guns- as the point which would need to be taken to force the Bavarians to retreat. D’Enghien meanwhile would make feints across the rest of the ridge to prevent Mercy from reinforcing.
However, while both generals were riding to investigate a report the Bavarians were retreating an overeager commander on the French left began his attack, the sound of gunfire triggering Turenne’s men to begin theirs as well. Given the events of the day however it seems unlikely that even the original plan would have been of much success- by the afternoon d’Enghien’s repeated attacks up the slopes towards the Bavarian positions had used up Turenne’s infantry, his own infantry and even the cavalry after they’d been told to dismount and attack on foot, resulting in heavy casualties and with virtually the entire army too exhausted to continue fighting. Their one saving grace was that the Bavarians were equally as exhausted, their horses weak from lack of fodder and while their losses were only 1,100 to the French 4,000, among them were Kaspar von Mercy, Franz’s brother, and it appears this loss essentially broke the General’s confidence in holding Freiburg.
D’Enghien was reinforced with 5,000 men stripped from every garrison in the area, and took three days rest enforced by even his desire to advance being tempered by the poor state of the troops. Further, when he finally did attack on August 9th it was with a wide flanking manoeuvre through the Glotter valley that forced Mercy to retreat down the St. Peter valley to intercept him. Mercy again secured the defensive position of St. Peter’s Abbey first, and repulsed an initial attack by the French vanguard, but with his army demoralised from retreating after such a long battle, his horses exhausted from having been saddled for 8 days continuously due to the repeated alarms, and the whole French army arriving as reinforcements, he chose to retreat in good order rather than risk the army being destroyed.
The French Conquest of the Rhineland
Freiburg had, if anything, been a narrow tactical victory for the Bavarians, but it would turn into an unexpected strategic disaster. Turenne successfully persuaded d’Enghien to avoid wasting time besieging Freiburg and instead turn north into the Lower Palatinate that was now virtually undefended due to the retreat of the Bavarians and the main Imperial army retreating into Bohemia. Baden was overrun in a matter of days. The fortress of Philippsburg, held by the Imperial army since 1635 but now only defended by 250 men, now came under siege from Turenne’s army as d’Enghien returned to Paris to overwinter in comfort there. Both Franz von Mercy and Duke Charles IV of Lorraine attempted to force the abandonment of the siege, the former occupying Mannheim and pretending to cross the river, the second laying siege to the small town of Bacharach nearby. Turenne however simply ignored the former, and responded to the latter by having 500 men construct a huge camp at Bacharach, convincing the Duke that he was about to face a much larger force and inducing him to retreat instead. Philippsburg fell after only three weeks, followed by Mainz and Speyer, which combined with the French finally taking the last holdouts against their occupation of the Duchy of Lorraine finally gave them a secure route to advance into Germany while avoiding the narrow passes of the Black Forest.
This was not in any way inevitable. Freiburg had been the longest and most bloody battle of a war full of long and bloody battles, and d’Enghien’s tactics of repeated attacks against defended positions coupled with his tendency to lead from the front meant that it would have been quite feasible for him to have died in during the battle, an incident that would almost certainly have seen the French army demoralised sufficiently to force a retreat. Even without this, Kaspar von Mercy surviving might well have given his brother sufficient greater confidence at holding his ground in the later stages of the battle- something which could have been disastrous to the Bavarian army if they didn’t have the supplies for another day of heavy fighting- or at least have meant he was quicker to react to the French moving away from Freiburg. A major defeat for the French here, instead of an equivalently inconclusive battle narrowly in Bavaria’s favour, could even have opened up the road for an advance to Breisach potentially eliminating the entire French position east of the Rhine.
As it was, Franz von Mercy was instead once more forced to take defensive actions in Swabia, for in 1645 Turenne prepared to advance once more, this time as part Torstensson’s grand pincer-movement against both Munich and Vienna.
Alex Richards is the author of Tippecanoe and Wallace Too, published by SLP