The Battle of Wagram was a military engagement of the Napoleonic Wars that ended in a costly but decisive victory for Emperor Napoleon's French and allied army against the Austrian army under the command of Archduke Charles of Austria-Teschen. The battle led to the breakup of the Fifth Coalition, the Austrian and British-led alliance against France. Wagram was the largest battle in European history up to its time.
In 1809, the French military presence in the Confederation of the Rhine was diminished as Napoleon transferred a number of soldiers to fight in the Peninsular War. As a result, the Austrian Empire saw its chance to recover some of its former sphere of influence and invaded the Kingdom of Bavaria, a French ally.
Wikipedia https://en.wikipedia.org/wiki/Battle_of_Wagram
Address 2232, Austria
Coordinates 48°16'43.103" N 16°34'2.996" E