IV Corps at Gołymin, Marshal Louis-Nicolas Davout's III Corps at Pułtusk, and Marshal Jean Lannes at Serock. Marshal Pierre Augereau's VII Corps stood in a reserve position behind the arc at Płońsk. Marshal Joachim Murat's Reserve Cavalry took up winter quarters in districts to the rear except for General of Division Louis Michel Antoine Sahuc's 4th Dragoon Division, which reported to Bernadotte, and General of Division Antoine Lasalle's Light Cavalry Division which patrolled Soult's front. Russian offensive In a council of war on 2 January 1807, Buxhöwden and Bennigsen determined to take the offensive against the French. They intended to move north into East Prussia with seven divisions before turning west to attack Napoleon's left flank. The plan called for one division to remain northeast of Warsaw to distract the French. This division would soon be joined by two more that were due to arrive from Moldavia under the command of Lieutenant General Ivan Essen. Lieutenant Generals Dmitri Mikhailovich Volkonski (9th Division) and Petr Ivanovich Meller-Zakomelski (10th Division) led the two units. The Russian leaders hoped to damage Napoleon's left wing and force the French army to fall back to the west bank of the Vistula. The positions gained would be used to launch a spring campaign that might drive the French back to the Oder River. Still jealous of his rival Buxhöwden, Bennigsen withdrew east to Tykocin with his six divisions rather than join his troops to the right wing of the army. He marched north for Goniądz where he found, to his delight, that Czar Alexander had appointed him army commander and recalled Buxhöwden. From there, he moved west to Biala Piska, arriving there on 14 January. Bennigsen left the 6th Division at Goniądz. Screened from Soult's cavalry screen by the Johannisburg Forest, Bennigsen's northward move into Masuria remained hidden from the French. The Prussian field force under General-Leutnant Anton Wilhelm von L'Estocq withdrew northward to Rastenburg (Kętrzyn). Meanwhile, Ney, finding his sector devoid of food and forage, disobeyed Napoleon's orders and advanced far northward in the direction of Königsberg. On the 11th his advance guard repulsed a Prussian attack on Schippenbeil (Sępopol). Three days later, Ney estimated that L'Estocq had 9,000 troops while General of Infantry Ernst von Rüchel garrisoned Königsberg with another 4,000. Livid at Ney for his insubordination, Napoleon nevertheless began to take measures in case the Russians reacted to the VI Corps leader's advance.