The Battle of Austerlitz, also known as the Battle of the Three Emperors, was one of Napoleon's greatest victories, where the French Empire effectively crushed the Third Coalition. On 2 December 1805 (20 November Old Style, 11 Frimaire An XIV, in the French Republican Calendar), a French army, commanded by Emperor Napoleon I, decisively defeated a Russo-Austrian army, commanded by Tsar Alexander I and Holy Roman Emperor Francis II, after nearly nine hours of difficult fighting. The battle took place near Austerlitz (Slavkov u Brna) about south-east of Brno in Moravia, at that time in the Austrian Empire (present day Czech Republic). The battle was a tactical masterpiece of the same stature as the ancient battles of Gaugamela and Cannae, in the 4th and 3rd centuries BC.