The Battle of Tuttlingen was fought in Tuttlingen on 24 November 1643. Those involved in the conflict were the French forces led by Marshal Josias Rantzau and the armies of the Holy Roman Empire and Spain led by Franz von Mercy. Technically, Mercy led a military forcecomposed of Imperial, Spanish, Bavarian, and Lorrainer troops. In early November the French-Weimarian forces had taken up winter quarters along the Danube in Tuttlingen. Outlying detachments were posted at Mühlingen and Möhringen. With the French inactive, Mercy convinced the other Imperial generals to join forces for a surprise attack on the French encampment. To maximize surprise, the Imperials approached from the south-east instead of further to the north where the Danube and the French garrison at Rottweil blocked their way. At mid-afternoon on 24 November, Johann von Werth led 2,000 cavalry in the first assault group against Möhringen and achieved instant success, riding down a French infantry regiment composed of Spanish prisoners of war. The Bavarian dragoons captured the French pickets posted near Tuttlingen, allowing the Imperials to seize with minimal opposition the lightly defended French artillery park in the cemetery outside town. The Weimarian cavalry in Mühlheim attempted to reinforce the French at Tuttlingen but were intercepted and defeated by Mercy's brother Kaspar. Kaspar then destroyed the Weimarian infantry remaining at Mühlheim. The French cavalry now fledthe scene. The captured guns were used to bombard the helpless French infantry in Tuttlingen and Möhringen, who capitulated the next day along with their commander Rantzau. The fighting lasted for a day and a half, not so much due to the effectiveness of Franco-Weimarian resistance but because of the disorganized and isolated nature of their detachments. The 2,000 strong French garrison in Rottweil surrendered a week later. Rantzau's army largely ceased to exist, the remnants retreating back across the Rhine River into Alsace. Moreover, Mercy held Rantzau, seven other generals, 9 colonels, 10 guns, the whole baggage and seven thousandFrench troops captive. Another 4,000 lay dead or wounded. The Weimarian army was permanently crippled by this disaster.
