On May 1804, Napoleon made himself Emperor of France, and, functionally though not in name, Emperor of the Italian Republic and the Confederation of Switzerland. With the Holy Roman Empire clearly on its way into the French sphere of influence, Holy Roman Emperor Francis II joined in the name-game and proclaimed himself Emperor of Austria soon after Napoleon's coronation. In 1805, Austria allied with Britain. When the Russian Czar, Alexander I, joined this group in April, the Third Coalition was born. (Prussia, under Frederick William III, stayed out of the coalition.
By 1805, Napoleon was preparing to attack England. He had forces massed on the French coast of the English Channel, and was preparing them for an amphibious assault. The Channel was heavily defended by Nelson's fleet, but England held no sizeable English army to stop Napoleon if his forces got through. Britain breathed a sigh of relief when word came through that a combined Russian and Austrian army was marching on France. Napoleon diverted his army from the invasion of England to handle this new threat, though he continued to put naval pressure on England. On October 21, 1805, the British fleet decimated Napoleon's fleet at the battle of Trafalgar, solidifying its stranglehold on the sea. Two months later, on December 2, 1805, Napoleon solidified his own hold on Europe by smashing the Russo-Austrian offensive in Moravia, at Austerlitz. The Russians retreated to Poland and the Austrians signed the Treaty of Pressburg, which gave Napoleon even more Austrian territory in Italy.
In 1806, Napoleon finally dissolved the tottering Holy Roman Empire, replacing it with the Confederation of the Rhine, with himself as its "protector". Prussia, which had stayed out of the Third Coalition, became concerned with Napoleon's expansion of power in Germany. Frederick William III foolishly went to war without any allies. He was soundly defeated at the battles of Jena and Auerstadt in October 1806 and forced to retreat east to Konigsberg. Along with the Confederation of the Rhine, Napoleon now controlled western Prussia, including Berlin.
Next, Napoleon pursued the Russians, overrunning them at Friedland on June 14, 1807. Alexander I was afraid of retreating into Russia lest a rebellion break out when fighting started on Russian soil. Instead, he negotiated the Treaty of Tilsit with Napoleon in July 1807, allying himself with Napoleon, and horrifying the other rulers in Europe. The Third Coalition was dead.
To add to the prestige of the ceremony, and to add a mark of validation and authority to his imperial status Napoleon invited the Pope to his coronation ceremony, held in the Cathedral of Notre-Dame in Paris. In this action, Napoleon hearkened back to the Pope's crowning of Charlemagne, the great Frankish emperor, in 800 AD. The Pope came to Napoeloen because he did not want to make an enemy, since Napoleon's military power in Italy was steadily increasing, threatening the Papal States and Rome. Although the Pope was present at the ceremony, Napoleon did not allow the Pope to crown him, for to do so might imply a tinge of allegiance or subservience to the Pope. Instead, Napoleon, ever the self-made man, placed the crown of empire on his own head, and then crowned Josephine empress.
Napoleon's planned invasion of Britain in 1805 could have been a disaster for the British. If he could get his forces past the British naval forces and on to the island, which barely had a land army, French control of Britain would be virtually insured. Intervention by Russia and Austria, even though it led to the defeat of both countries, therefore may have saved Britain, preparing the way for Napoleon's later downfall.
The Battle of Trafalgar, during which Admiral Nelson lost his life, established Britain's naval supremacy for the rest of the Napoleonic era, and even for the rest of the 19th century. Napoleon, however, still seemed unbeatable on land. His control of Europe was rapidly growing, and if he was not stopped soon, control of the resources of all of Europe would eventually allow him to build a Navy large enough to beat the more skillful British at sea.
Alexander I was an interesting historical character. While Britain remained Napoleon's archenemy, we could well consider Alexander as Napoleon's "foil". Like Napoleon, Alexander controlled a vast territory, and was one of the most powerful forces in Europe. Alexander also considered himself an "enlightened despot". Although a czar in the Russian tradition, he had been educated by a very liberal Swiss tutor, and had a very progressive, modern outlook. He wanted to rationalize and modernize the Russian state, and he surrounded himself with educated advisors for that purpose. He saw himself as Napoleon's rival in Europe, and he was fairly original as monarchs go, advocating an idea of "collective security" for all of Europe, by which all of the powers would work together to make sure no one nation grew too powerful, so it could dominate all the other nations. Thus, he wanted the other nation to ally against whoever was most powerful, at this time France. But his opposition to France was not only based on rational calculations of "collective security", for Alexander was genuinely jealous of Napoleon's power and influence. Furthermore, his anti- Napoleonic stand was sweetened by a British offer to pay Alexander 1.25 million pounds for every 100,000 soldiers he raised to oppose Napoleon. Finally, Alexander wanted what Russian rulers always want: Poland. Poland would serve as a "buffer" between Russia and invasion from Western Europe, and it would allow the czar to extend his influence westward, into central Europe, and thereby gaining power in European affairs.
Why did Alexander ever agree to ally with Napoleon in the Treaty of Tilsit? Napoleon, always crafty, managed to appeal to Alexander's ego. He said that he and Alexander were alike, and that while Napoleon's destiny was an empire in Europe, Alexander would be the emperor of the East, ruling Turkey, India, and the like. Together, said Napoleon, nothing could stop them. Napoleon also claimed that Alexander's problems were caused by the "real enemy", Britain. Given his dire straits, Alexander allowed himself to believe Napoleon and signed the treaty.