The military career of Napoleon Bonaparte spanned over 20 years. As emperor, he led the French Armies in the Napoleonic Wars. He is widely regarded as a military genius and one of the finest commanders in world history. He fought 60 battles, losing only seven, mostly at the end. The great French dominion collapsed rapidly after the disastrous invasion of Russia in 1812. Napoleon was defeated in 1814; he returned and was finally defeated in 1815 at Waterloo. He spent his remaining days in British custody on the remote island of St. Helena.