When Galen again attacked the Dutch Republic six years later in the Franco-Dutch War, he was in alliance with Louis XIV, who helped him take Groenlo. His troops went more east and north and conquered not only Deventer and Coevorden. His army got stuck before the city of Groningen, failing to occupy the coast in the north, because of the deliberate flooding of the fields and marshes that became almost impassible. In October 1674 he withdrew his troops from the Dutch Republic and gave up his attempts to restore Catholicism to the Eastern provinces. In 1675 he deserted his former ally, and fought for the emperor Leopold I against France. In conjunction with Brandenburg and Denmark he attacked Charles XI of Sweden, and conquered the Duchy of Bremen in the Bremen-Verden Campaign during the Swedish-Brandenburg War. Von Galen died at Ahaus.