The War of the Fifth Coalition commenced as the Austrian Empire decided to take military action against the Napoleonic forces that had expanded significantly across Europe. On April 10, 1809, Austrian troops crossed into Bavaria, a territory belonging to the Kingdom of Bavaria, which was a satellite state of France at the time. The invasion was part of Austria's broader strategy to recover territories lost in previous conflicts with Napoleon, particularly the fallout from the Treaty of Pressburg in 1805.

Austrian military leadership, under figures such as Archduke Charles, aimed to capitalize on what they perceived as French overreach and to unearth a combined European resistance against the tyranny of Napoleon. The invasion was bolstered by some initial successes, and Austria sought to rally other states to their cause. However, the French Emperor was quick to respond with reinforcements, leading to a series of conflicts that saw much of Central Europe engaged in battle.

The escalation of hostilities led to several notable battles, including the Battle of Eckmühl and the Siege of Regensburg. Austria's efforts were ultimately thwarted, but the offensives exemplified the fervor for nationalism and territorial integrity that characterized the era. The series of conflicts during the Fifth Coalition laid the groundwork for future developments in European alignment and the eventual decline of Napoleonic power.