What happened December 1805 AD

The Battle of Austerlitz (2 December 1805/11 Frimaire An XIV FRC), also known as the Battle of the Three Emperors, was one of the most important and decisive engagements of the Napoleonic Wars. In what is widely regarded as the greatest victory achieved by Napoleon, the Grande Armée of France defeated a larger Russian and Austrian army led by Emperor Alexander I and Holy Roman Emperor Francis II. The battle occurred near the town of Austerlitz in the Austrian Empire (modern-day Slavkov u Brna in the Czech Republic). Austerlitz brought the War of the Third Coalition to a rapid end, with the Treaty of Pressburg signed by the Austrians later in the month. The battle is often cited as a tactical masterpiece, in the same league as other historic engagements like Cannae or Gaugamela.

At this critical juncture, both Tsar Alexander I and Holy Roman Emperor Francis II decided to engage Napoleon in battle, despite reservations from some of their subordinates. Napoleon sent his army north in pursuit of the Allies, but then ordered his forces to retreat so that he could feign a grave weakness. At the Battle of Austerlitz, in Moravia on 2 December, he deployed the French army below the Pratzen Heights and deliberately weakened his right flank, enticing the Allies to launch a major assault there in the hopes of rolling up the whole French line.

The Allied disaster at Austerlitz significantly shook the faith of Emperor Francis in the British-led war effort. France and Austria agreed to an armistice immediately and the Treaty of Pressburg followed shortly after on 26 December.