Eugene Beauharnais, who commanded the relics of the Grand Army, after suffering a reverse at Mockern, had retired to the line of the Elbe; and French garrisons were thus left isolated in Danzig, Modlin, Zamosc, Glogau, Kuestrin, and Stettin.[294] Napoleon's first plan of an advance direct to Stettin and Danzig having miscarried, he now sought to gather an immense force as secretly as possible near the Main, speedily to reinforce Eugene, crush the heads of the enemy's columns, and, rolling them up in disorder, carry the war to the banks of the Oder, and relieve his beleaguered garrisons by way of Leipzig and Torgau.

The plan would have the further advantage of bringing a formidable force near to the Austrian frontier, and holding fast the Hapsburgs and Saxons to the French alliance.
Meanwhile the allied army was pressing westwards with no less determination.

The Czar and King had addressed a menacing summons to the King of Saxony to join them, but, receiving no response, invaded his States.

Thereupon Frederick Augustus fled into Bohemia, relying on an offer from Vienna which guaranteed him his German lands if he would join the Hapsburgs in their armed mediation.[295] For the present, however, Saxony was to be the battlefield of the two contending principles of nationality and Napoleonic Imperialism.
They clashed together on the historic ground of Luetzen.

Not only the associations of the place, but the reputation of the leaders helped to kindle the enthusiasm of the rank and file.