The Kingdom of Bavaria foundation dates back to the ascension of prince-elector Maximilian IV Joseph of the House of Wittelsbach as King of Bavaria in 1805. The 1805 Peace of Pressburg allowed Maximilian to raise Bavaria to the status of a kingdom. The King still served as an elector until Bavaria seceded from the Holy Roman Empire on 1 August 1806. The Duchy of Berg was ceded to Napoleon only in 1806. The new kingdom faced challenges from the outset of its creation, relying on the support of Napoleonic France. The kingdom faced war with Austria in 1808 and from 1810 to 1814, lost territory to Württemberg, Italy, and then Austria. In 1808, all relics of serfdom were abolished, which had left the old empire.

During the French invasion of Russia in 1812 about 30,000 Bavarian soldiers were killed in action. With the Treaty of Ried of 8 October 1813 Bavaria left the Confederation of the Rhine and agreed to join the Sixth Coalition against Napoleon in exchange for a guarantee of her continued sovereign and independent status. On 14 October, Bavaria made a formal declaration of war against Napoleonic France. The treaty was passionately backed by the Crown Prince Ludwig and by Marshal von Wrede. With the Battle of Leipzig in October 1813 ended the German Campaign with the Coalition nations as the victors.

With the defeat of Napoleon's France in 1814, Bavaria was compensated for some of its losses, and received new territories such as the Grand Duchy of Würzburg, the Archbishopric of Mainz (Aschaffenburg) and parts of the Grand Duchy of Hesse. Finally, in 1816, the Rhenish Palatinate was taken from France in exchange for most of Salzburg which was then ceded to Austria (Treaty of Munich (1816)). It was the second largest and second most powerful state south of the Main, behind only Austria. In Germany as a whole, it ranked third behind Prussia and Austria.a