Although considered an inconsequential minor French noble living in exile after the Revolution and retired from war, the life of Louis Antoine de Bourbon, duc d'Enghien, proved to be a crucial moment for Napoleon's relations with the crowns of Europe.
Armée de Condé. D'Enghien distinguished himself in battle, but the royalist invasion of Revolutionary France proved ineffectual. In 1801, the army was disbanded, and d'Enghien retired to Baden along the Rhine, where he married the niece of Cardinal de Rohan and lived peaceably.
Meanwhile, France underwent another major coup as General Napoleon Bonaparte, fresh from his expeditions in the Middle East, seized Paris. While much of France welcomed his command, many others still felt the Bourbons were the rightful rulers. Royalists such as Georges Cadoudal and General Jean-Charles Pichegru formed conspiracies that attempted to overthrow the tyrannical First Consul Napoleon and return the crown to the Bourbon Louis, Count of Provence. When the two joined forces, Napoleon's network of police and personal guard, championed by Anne Jean Marie Rene Savary, caught and executed them.
Beleaguered by the constant praise of the Bourbons, Napoleon determined that "all of France [must] realise that Bourbon blood, so sacred to Royalist partisans, was no more sacred to him than the blood of any other citizen in the Republic," according to French writer Alexander Dumas. To do so, Napoleon ordered the arrest of d'Enghien on grounds of conspiracy with Cadoudal and Pichegru. The duke was believed to be in contact with another general-of-the-Revolution-turned-royalist, Charles Dumouriez, and dragoons sneaked into Baden, capturing d'Enghien and bringing him before a military tribunal.
While the duke was in custody, the truth came out that d'Enghien's company was a case of mistaken identity, and Napoleon hurried to rewrite the charges to something else. As he did, however, his wife Josephine begged him to release the duke. She noted that Napoleon may change the mind of France with the duke's blood, but it would also affect the minds of Europe, who had already formed two coalitions against France, the last war ending in 1802 with the Treaty of Amiens. Rumors of another coalition trickled through Europe as Britain declared war on France by invading Malta in 1803, but no decisions on the Continent had been made. Napoleon begrudgingly agreed, and on March 21, 1804, he met personally with d'Enghien to discuss peace between himself and the Bourbon blood.
The news of Napoleon's leniency toward the Bourbons spread throughout France and across Europe. Napoleon's regime was suddenly seen as a welcome change from the bloodthirsty revolutionaries and seemed to have proven itself understanding in royal affairs. Napoleon, while powerful, might only be an enemy to anyone who provoked him, namely Britain with its violation of the Treaty of Amiens. Despite his great efforts, British Prime Minister William Pitt could not persuade any of the great nations of Europe except Alexander I's Russia to ally with them in yet another Coalition against France. The era of the Revolution was seen as gone, with the new generation of nobles already establishing its own status quo.
While Europe was pacified, France was still on the brink with its royalists determined to bring back a Bourbon king. To entrench himself, on December 2, 1804, Napoleon crowned himself "emperor", fulfilling months of planning and government maneuvers. While many were suspicious of his taking of the crown from Pius VII rather than letting the pope place it upon Napoleon's head, many Europeans saw it as the formalization of the new France. Rather than taking the suspicion of Napoleon as a pretender, the title actually became embraced by many other nobles in Europe. Napoleon's fame in France, meanwhile, became solidified.
Still, war dragged on with Britain in a stalemate. Britain's powerful navy held a blockade on France and safely guarded the English Channel, preventing Napoleon from invading despite having the largest military in Europe. Prussia and Austria served as buffers against Russia, and the Nordic countries felt ill will toward Britain after the English invasion of Denmark to break up the neutral Second Coalition of the North. With naval defeat at Trafalgar in October of 1805, Napoleon's enormous Grande Armee stood useless. Napoleon decided to invest in rebuilding his fleet in the Mediterranean and then striking out southward to Tunisia, where he planned to overthrow the Bey of Tunis and end attacks by pirate corsairs upon French. The war spread to the Kingdom of Naples, where Napoleon's troops clashed with the Anglo-Russian force stationed to protect it. Austria balked at Napoleon's domination of Italy and joined the war, only to be quickly defeated and impressed into becoming France's ally.
Naval warfare in the Mediterranean continued for years. Napoleon repeatedly built up fleets only to have them destroyed by the experienced British navy. Upon land, however, Napoleon made great advances, seizing southern Italy and capturing the north coast of Africa. Finally, in 1812, Napoleon felt confident enough in his naval supply chain through Austria for his massive invasion of India, again passing through Egypt as he had years before. The Ottoman Empire attempted neutrality, but it was forced onto the side of the British and Russians. By 1815, Napoleon's army was cut off from France by a second grand naval battle in Alexandria, and Napoleon found himself marching through Persian deserts without hope of return home. The army crumbled around him and was routinely victim to ambush by locals. He attempted to escape back to France but was apprehended as his ship sailed around Gibraltar at night. Imperial France collapsed, and the Bourbon Louis XVIII was restored to the throne.
In reality, the duke was executed. Sweden broke off relations with France over the affair, and Pitt successfully achieved an alliance in which Swedish Pomerania could be used as a base to land troops on the Continent. Other nations followed, and the War of the Third Coalition soon began. After four more coalitions, Napoleon would finally be defeated in 1815, and Bourbons returned to the throne of France.