Even as he was cementing his hold on political power, Napoleon was leading the French armies to victory against the foreign coalition. He continued the existing focus on total war that had begun with the levée en masse, but he enhanced it further by paying for the wars (and new troops) with loot from his successful conquests. He ended up controlling a million soldiers by 1812, the largest armed force ever seen. From 1799 to 1802, he defeated Austrian and British forces and secured a peace treaty from both powers, one that lasted long enough for him to organize a new grand strategy to conquer not only all of continental Europe, but (he hoped), Britain as well. That treaty held until late 1805, when a new coalition of Britain, Austria, and Russia formed to oppose him.

His one major defeat during this early period was when he lost the ability to threaten Britain itself: in October of 1805, at the Battle of Trafalgar, a British fleet destroyed a larger French and allied Spanish one. The British victory was so decisive that Napoleon was forced to abandon his hope of invading Britain and had to try to indirectly weaken it instead. Even the fact that the planned invasion never came to pass did not slow his momentum, however, since the enormous army of seasoned troops he assembled for it was available to carry out conquests of states closer to home in Central Europe.

Thus, despite the setback at Trafalgar, the years of 1805 and 1806 saw stunning victories for Napoleon. In a series of major battles in 1805, Napoleon defeated first Austria and then Russia. The Austrians were forced to sign a treaty and Vienna itself was occupied by French forces for a short while, while the Russian Tsar Alexander I worked on raising a new army. The last major continental power, Prussia, went to war in 1806, but its army was no match for Napoleon, who defeated the Prussians at the Battle of Jena and then occupied Berlin. Fully 96% of the over 170,000 soldiers in the Prussian army were lost, the vast majority (about 140,000) taken prisoner by the French. In 1806, following his victories over the Austrians and Prussians, Napoleon formally dissolved the (almost exactly 1,000-years-old) Holy Roman Empire, replacing much of its territory with a newly-invented puppet state he called the Confederation of the Rhine.

After another less successful battle with the Russians, Napoleon negotiated an alliance with Tsar Alexander in 1807. He now controlled Europe from France to Poland, though the powerful British navy continued to dominate the seas. His empire stretched from Belgium and Holland in the north to Rome in the south, covering nearly half a million square miles and boasting a population of 44 million. In some places Napoleon simply expanded French borders and ruled directly, while in others he set up puppet states that ultimately answered to him (he generally appointed his family members as the puppet rulers). Despite setbacks, Napoleon’s forces continued to dominate continental Europe through 1813; attempts by the Prussians and, to a lesser extent, Austrians to regain the initiative always failed thanks to French military dominance.