Bernard's Upper Rhine Campaign

Background

The Thirty Years' War kicked off in 1618 when the mostly Protestant Bohemian Estates picked the Calvinist Frederick V for their crown instead of the hardline Catholic Ferdinand II of Habsburg. Most of the Holy Roman Empire stayed out of it, and the Bohemian Revolt was put down after two years. With backing from Maximilian of Bavaria, a Liga-Spanish army moved into Frederick's German lands and forced him to flee to the Dutch Republic. When Maximilian took over Frederick's role as elector of the Palatinate, the war shifted, pulling in Protestant powers like Saxony, Hesse-Kassel, Brandenburg-Prussia, and Denmark-Norway.

In 1630, Sweden's Gustavus Adolphus invaded Pomerania, partly to aid fellow Protestants but also to grab control of Baltic trade, a key source of Swedish income. Even after Gustavus died at Lützen in November 1632, Sweden kept fighting, though their goals clashed with Imperial states like Saxony and their rival Denmark. In 1634, Bernard of Saxe-Weimar and Gustav Horn got crushed by the Cardinal-Infante Ferdinand at Nördlingen. That disaster left the Swedish army in rough shape—Bernard lost 12,000 to 14,000 of his 25,700 men—and he could not stop Johann von Werth from sweeping west into Baden-Württemberg.

Bernard gave up Heilbronn and fell back to Mainz. Only Hohentwiel and Ulm held out in Swabia, and things got worse when Philipp von Mansfeld's Imperial army moved south and Matthias Gallas's force moved north. With few options, Bernard offered his services to the French, who agreed and promised him his own duchy in Alsace. Bernard, leading 12,000 to 16,000 troops, joined up with Louis de La Valette, who had 10,000, but two-thirds of La Valette's men deserted.

Frankfurt am Main and Mannheim were taken, and Mainz's surrender made Bernard's position even worse. He pulled back first to Alsace, then through Basel and into Mömpelgard.

Campaign

In early February 1638, prodded by the French government, Bernhard advanced his army of 6,000 men and 14 guns to the Rhine. Arriving at the important crossing point of Rheinfelden, he prepared to invest the town from the south while using the ferry at Beuggen to throw troops across the river for a northern investment. The attack was planned for March 1. To prevent this, the Imperialists under Count Federico Savelli and Johann von Werth moved with 2,600 infantry and 4,500 cavalry through the Black Forest to attack Bernhard and relieve the town.

Rheinfelden held out stubbornly as Werth and Savelli approached. Unable to deploy, they took a more difficult road parallel to the river and headed west to Rheinfelden. Bernard used the four hours it took them to ferry over 600 musketeers and 8 light guns, and concentrated the cavalry already north of the river under Georg Christoph von Taupadel on higher ground above the town. Taupadel charged as the Bavarian cavalry tried to deploy from the road at Karsau.

The Bavarians were thrown back, but left Rohan and Johann Phillip von Salm-Kyrburg; Salm was mortally wounded, while Johann Ludwig von Erlach and Rohan were captured. Savelli and the Imperial Infantry now arrived and gained the heights. Bernard held his position until night, then slipped past the enemy to retreat eastwards along the river to Säckingen, abandoning at least three guns and 150 men. The absence of pursuit was unsurprising given Savelli and Werth had just force-marched their men through the mountains in winter on low rations.

Bernard regrouped at Lauffenburg, 14 km upstream, joined by the rest of his army from the south bank on March 2. He undertook one of the risky maneuvers that made him famous, setting off early the next day back along the north bank to Beuggen, collecting 3 artillery pieces that Werth and Savelli had failed to find. Bernard was spotted by Imperial pickets around 7 am.

Aftermath

After his victory, Bernard marched his army back to Breisach, his objectives achieved. He intended to solidify his hold over his Duchy in Alsace and Breisgau, hoping to gain more freedom from French control. But his health was failing, and he died at Neuenburg am Rhein just as a new campaign began. The fortress commander, Johann Ludwig von Erlach, accepted a bribe and handed Breisach over to France.

Bernard was buried there temporarily; his body was not moved to Weimar for sixteen years. The bulk of his army stayed with the French commander Jean-Baptiste Budes, Comte de Guébriant, who brought it under direct French authority. Guébriant went on to score major wins at Wolfenbüttel and Kempen, but was fatally wounded at Rottweil in 1643. His replacement, Josias von Rantzau, made a critical error at Tuttlingen, leaving the French bottled up at Hohentwiel and wiping out most of what Bernard had achieved.

Bernard's campaign did succeed in severing the Spanish Road, which forced the Spanish to rely on a much riskier sea route to supply their forces in the Spanish Netherlands.