The Battle of Austerlitz (Czech: Bitva u Slavkova) also known as the Battle of the Three Emperors, was one of Napoleon's greatest victories, effectively estroying the Third Coalition against the French Empire. On December 2, 1805 (November 20, Old Style), a French army, commanded by Emperor Napoleon I, decisively defeated a Russo-Austrian army, commanded by Tsar Alexander I, after nearly nine hours of difficult fighting. The battle took place at Austerlitz (Slavkov u Brna) about 20 km (12 miles) east of Brno in Moravia. The battle is often regarded as a tactical masterpiece.