Reduced to poverty through the loss of his paternal inheritance, he took
holy orders; but this did not prevent him from fighting on the side of Emperor
Ferdinand III during the concluding stages of the Thirty Years' War. In 1650 he was elected
prince-bishop of Münster, succeeding
Ferdinand of Bavaria. After restoring a degree of peace and prosperity in his principality, Galen had to contend with a formidable insurrection on the part of the citizens of Münster; but in 1661 this was solved by the occupation of the city. At the head of the largest ecclesiastical principality of the Holy Roman Empire, the prince-bishop, who maintained a strong army, became an important personage in Europe. In 1664, he was chosen one of the directors of the imperial army raised to fight the
Turks, but his troops came too late to fight; after the peace which followed the
Christian victory at the
Battle of St. Gotthard in August 1664, he aided
Charles II of England in his
Second Anglo-Dutch War with the
Dutch, until the intervention of
Louis XIV and
Frederick William, Elector of Brandenburg compelled him to make a disadvantageous peace in 1666 in
Cleve. 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–Norway 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. He proved himself anxious to reform the
church, although his chief energies were directed to increasing his power and prestige, in the course of which he succeeded in getting rid of the foreign armies which had been occupying
Westphalia since the
Peace of Westphalia in 1648. ==In popular culture==