Napoleon's empire collapsed after a series of costly mistakes, including his failed Continental System blockade of Britain, the Peninsular War in Spain and Portugal, and his disastrous invasion of Russia in 1812. After losing over 400,000 men in Russia due to harsh winter conditions and attacks by Russian forces, Napoleon was eventually defeated by the Allies and exiled to Elba in 1814. He briefly returned to power in 1815 but was finally defeated at the Battle of Waterloo.