After defeating Conquering Emperor Napoleon at the Battle of La Rothière , the two main Allied armies under Austrian Field Marshal Karl Philipp , Prince of Schwarzenberg and Prussian Field Marshal Gebhard Leberecht von Blücher separated Forming_relationships .

Schwarzenberg 's southern advance was slow while the Prussian field marshal 's march represented a more serious threat Preventing_or_letting to Paris .

Leaving part of his forces to hold off Defending Schwarzenberg , Napoleon massed Motion 30,000 troops to deal with Blücher , who allowed Giving his 57,000-man army to become badly spread Dispersal out .