In 1803, Napoleon sold the Louisiana Territory to the United States, to pay for his wars. Napoleon planned to invade Great Britain but never did. In 1805, off the southwest coast of Spain, Britain defeated a combined French and Spanish fleet. Napoleon then decided to cut off Britains trade, but Spain and Portugal still allowed British ships in there ports. In 1807, Napoleon attacked the Iberian Peninsula (where Spain and Portugal are located). That drug on for five years (Britain aided the Spanish) depriving Napoleon of troops. Russia had agreed to cut off trade with Britain, but Tsar Alexander I (the ruler of Russia) decided against it in 1810. Napoleon wanted revenge, so he assimilated the people he had conquered into his army. This included Germans, Dutch, Swiss, Italians, Poles, and Lithuanians. He gathered over six hundred thousand troops and invaded in June 1812. Every time Napoleon attacked, the Russian force pulled back, burning their own supplies and villages. They did this so that there would be nothing left Napoleon's troops could use. Napoleon's troops marched into Moscow when a fire started burning two-thirds of the city. The Russians re-enforced their army and refused to surrender. Realizing that they could not survive the harsh Russian winter, Napoleon retreated on October 18th. Fewer than forty thousand survived due to starvation and disease, many deserted. Some were killed or captured by the Russians when they fell behind. Austria, Britain, Russia, Sweden, and Prussia made an alliance. They want to destroy Napoleon while his forces were weak. They drove Napoleon out of Germany in 1813. In 1814, the alliance made its way to Paris, forced Napoleon to surrender, and exiled him from France. They gave him a small unimportant place to rule called Elba, northwest of Italy. Napoleon made his way back to France with a thousand followers and gained the people's support. Napoleon's plan was to raise an army and attack British and Prussian forces (at a town called Waterloo, now in modern-day Belgium) before they could unite. The Duke of Wellington commanded the British troops and became victorious with Prussian reinforcements. Napoleon went to the Atlantic coast of France and surrendered to the British. He was then exiled to St. Helena, a small island in the Atlantic Ocean.