Turenne was in command of the advanced guard, and his courage and activity alone saved the army from complete destruction--seizing upon defiles, overthrowing the enemy who barred the passages, and enabling the army to recross the Rhine with numbers diminished only by sickness, fatigue, and hunger.

At the siege of Saverne, Turenne led the French troops to the attack after three repulses, and succeeded in gaining a footing in the town, but received himself a very severe wound in the arm with a musket ball.

During the following year several towns were captured but no decisive operations took place.
In 1638, the Duke of Saxe-Weimar gained some great successes, defeated the Imperialists with heavy loss at Rheinfelden, and besieged Breisach, the key of southern Germany.

The Imperialist army marched to relieve the place, but reinforcements were sent from France under the command of Turenne and Longueville.

Three battles were fought and the Austrians driven off.