The Waldecks had a tradition of military service in the Dutch Army.&lt;br&gt; Prince Georg Friedrich of Waldeck had already led the Dutch army in the War of the Grand Alliance. In the War of Austrian Succession, Karl was appointed as commander of the Dutch Army by the States-General of the Netherlands, as counterbalance to William IV, Prince of Orange, who relied completely on his brother-in-law the Duke of Cumberland. The Dutch army under Waldeck's command was defeated in the Battle of Fontenoy, the Battle of Rocoux and the Battle of Lauffeld. In 1746, Karl became Fieldmarshal of the Holy Roman Empire.