Though Napoleon's unquenchable thirst for military adventurism eventually cost him both his throne and his freedom during the Napoleonic Wars of the late 18th and early 19th centuries, the French emperor was not easily defeated even when most of Europe's nations united against him.

In 1812, Napoleon's Russian adventure gutted his veteran army, depriving him of the majority of his finest and most loyal soldiers. Those who remained formed the hard core of his new armies, but the Russian fiasco damaged their health and embittered their previously unquestioning loyalty. Napoleon raised vast new armies, but circumstances compelled him to fill the ranks with raw recruits.

These factors set the stage for the second setback, which essentially sealed the fate of Napoleon's empire. The four-day Battle of Leipzig in October 1813, romantically but accurately dubbed the "Battle of the Nations," proved the decisive encounter of the War of the Sixth Coalition and essentially determined the course the Napoleonic Wars took from that moment forward.

Although Napoleon was exiled, he was allowed to retain the title of Emperor and was given de facto control over Elba. But it should not be surprising the man who once ruled Europe was not content with the island of Elba. Separated from his family and cast away on a small island, Napoleon attempted suicide by taking a poison pill, but he had first carried the pill with him on the retreat from Moscow, rightly concerned about an uncertain fate at the time. The aging process had fatally weakened the pill, which stopped it from fatally weakening Napoleon.

Though the emperor busied himself developing the island's industries and had established a miniature army and navy, he must still have found time to brood upon his situation and could not have helped but think of himself as reduced to laughing stock. The "Emperor of Elba" was a poor title for a man who had once ruled over more than half of mainland Europe. Even some of Napoleon's old Marshals, like Murat, now controlled more territory than the man who had raised them in the first place. To add insult to injury, the salary he had been promised in the Treaty of Fontainebleau and that was meant to keep him in relative luxury was often late and sometimes failed to arrive at all. Coupled with his deteriorating health and the express refusal of the Austrian court to let him speak or write to his wife and son, Napoleon must have felt himself well and truly slighted. Beaten, but not defeated, he resolved to show the Coalition powers he could still make Europe tremble.

Of all the incredible military feats Napoleon accomplished, none were more impressive than his escape from Elba and his return to France, which was literally a bloodless revolution. On February 26, 1815, Napoleon escaped from Elba, and in a desperate gamble, he landed on the French mainland with less than a thousand men and marched on Paris.
What happened next was truly remarkable. An infantry regiment was sent to intercept Napoleon and his men, but Napoleon rode up to them alone and shouted, "Here I am. Kill your Emperor, if you wish." Upon seeing their once invincible leader before them, the soldiers mutinied and went over to his side en masse. Other corps soon followed, and in no time at all Napoleon found himself at the head of an army marching on Paris. The newly reinstituted Bourbon monarch fled the city, and so, with barely a shot fired, Napoleon found himself enthroned as emperor once more. In an astonishing feat of political chutzpah and military organization, within three months he had seized power anew and rebuilt his veteran forces to a strength of 200,000 men. Of these, 128,000 were assembled into the Armee du Nord, under Napoleon's personal command. Its mission quickly became the destruction of the British-Allied and Prussian armies assembling near Brussels, which would lead to Waterloo, arguably the most famous battle in European history.