In 1733 Frederick William II was promoted to lieutenant general. He participated in campaigns along the Rhine in 1734 and 1735 during the War of the Polish Succession. King Frederick II of Prussia was displeased with Frederick William after the Battle of Mollwitz during the First Silesian War in 1741. His regiment had been held in reserve and arrived on the battlefield too late to contribute to the battle. Unaware of the situation, he passed by several Austrian units. Nevertheless, King Frederick the Great was fond of the duke, whom he referred to as "gute alte Holsteiner" ("good old Holsteiner"). The duke was promoted to field marshal later that year and posted in Königsberg, the capital of East Prussia. He was also a recipient of the Order of the Black Eagle.