4. Battle Of Leipzig (1813)
Waterloo is the more famous battle, but Leipzig proved catastrophic to Napoleon's reign. The invasion of Russia had failed, with the Grande Armee failing to meet the Russian forces in a decisive battle and being forced to retreat due to the winter conditions. On top of that, some of the German provinces were on the brink of revolt, leaving him little choice but to retreat beyond the Elbe River. A coalition of Russian, Prussian, Austrian and Swedish forces met Napoleon at Leipzig, where he had set up defensive positions in surrounding towns and planned to use the open terrain for cavalry manoeuvres. He hoped to defeat the Russians and Austrians before the others arrived, but Prussia's Marshal von Blucher arrived earlier than expected and set up his forces in the area Napoleon hoped to outflank the Austrians and Russians. Four columns of Austrians and Russians attacked first, but, covered in fog, the attacks were uncoordinated and the French troops drove them back. The first day ended in stalemate, with both sides attacking and counter-attacking, but failing to deliver a decisive blow. Unfortunately for Napoleon, fresh troops continued to arrive for the coalition, and, when their attacks improved, he was forced to retreat. During the retreat a major problem occurred, when the officer in charge of demolishing a bridge blew it when it was still crammed with French troops, leaving many trapped. Around 560,000 troops took part in the battle the highest number until WWI and an estimated 127,000 were killed. The Battle of Leipzig forced Napoleon on the back foot, with defeats coming at La Rothiere and Arcis-sur-Aube. It ended with his abdication in 1814. If Napoleon had won, he would've had a large enough force to subdue Wellington in Spain. His win would also see the continuation of the Continental System and the trade embargo against British goods exports fell between 25% and 55% during the embargo and had a large effect on British trade. It's hard to imagine all-out war not breaking out between Napoleonic France and Britain.