Due to its successes against Austria in the first two Silesian Wars and the Seven Years War, the Prussian army is considered to have been Europe’s best in the middle of the eighteenth century. Yet half a century later the once-mighty forces of Frederick the Great were crushed on the fields of Jena and Auerstädt. The short War of the Bavarian Succession (1778-1779), the last war of Frederick the Great is often considered as a first stage in the rapid decline of Prussia’s Ancien Régime forces.However, this study takes a fresh view on this conflict. It gives a critical analysis of the strength and limitations of Frederick’s War machine, before offering a narrative of this forgotten war, which, because of its lack of battles, was scoffed by contemporaries as a ‘potato war’, as soldiers struggled more to find food than to fight the enemy. While the war definitely revealed weaknesses within the Prussian military regime, it was not necessary for Frederick to win battles and campaigns as long as he was able to achieve his political goals.This fresh study will change our view of Prussian military effectiveness in the eighteenth century.