Napoleon decided to invade Russia. He began to position troops near the western border of Russia, and this made Czar Alexander I (the Russian ruler at the time) very nervous. Napoleon marched 600,000 soldiers across the border of Russian in June of 1812. However, many of these soldiers felt no loyalty or nationalism towards France or Napoleon because they were soldiers captured from former battles. Between hunger, extreme heat & disease, the French ranks were soon thinned. When they finally clashed with Russian opposition, the casualties were high for the French, around 250,000 dead. Napoleon and his army were forced to retreat back into France before making it to Moscow. Only 94,000 out of the 600,000 soldiers remained alive and made it back to France.