In January 1812, the Grand Army consisted of 600,000 men split into 40 divisions of infantry and 25 divisions of cavalry. Only 270,000 of them were native Frenchmen.

   The Grand Army was a conglomerate of soldiers from countries under Napoleon's direct control: The Kingdom of Italy, The Grand Duchy of Warsaw, The Kingdoms of Bavaria, The Kingdoms of Saxony, The Kingdoms of Westphalia, Anhalt, Baden, Berg, Croatia, Dalmatia, Denmark, Hesse-Darmstadt, Illyria, Lippe, Mecklenberg, Naples, Spain, Switzerland, Württemberg. The exception being two regiments of Portugese soldiers.

    In June 1812, the Russian Armed Forces were only 215,000 strong. Barclay De Tolly's First Army of the West was in Memel with 110,000 soldiers, and the Second Army of the West was in Vilna with 60,000 soldiers under Prince Bagration. Tormasov's Third Army of the West was stationed south of the marshes with 45,000 men to keep an eye on the Austrians. Other armies were being formed from Finland and Romania, but only the three Armies of the West were available to resist Napoleon's Grand Army.

  This immense army outnumbered Russia's soldiers three to one. This many people poses huge logistic problems. Normally, the French armies forage in the towns and farms they pass through. Not too native-friendly, but effective. But, to prepare to feed all of these horses and people during winter, Napoleon arranged for supplies to be set up in eight cities. One depot in Danzig held enough rations for 400,000 men for 50 days. To create such a setup, an elaborate supply train of 3,024 four-horse wagons, 2,400 one-horse wagons, and 2,400 ox wagons was set out, as well as whatever sea vessels could supplement. It is believed that Napoleon knew there would not be enough supplies for the troops and grass for the horses, and planned to have time for the wagons and barges to shuttle supplies to the depots during the unopposed march. These preparations were based on the assumption that the campaign would be decisively short and victorious.

    On June 24th, the troops began to cross the Niemen River into Russian territory. Four days later, they reached Vilna without any opposition or sign of the Russian army. Napoleon was a bit disappointed with this, and declared,

   Foraging was starting to get scarce, and 5,000 horses died from being fed on rye that was too green. This forced them to abandon 600 weapons and amunitions wagons.

   Barclay de Tolly's strategy to get behind Napoleon was to split from the Second Army and drop back 150 miles to the east bank of the Dvina River. Then while Napoleon was stunned, Bagration's group would surround Napoleon and force them to surrender. Barclay de Tolly's group dropped back as planned, but things went awry when the prepared entrenched camp was too small and hard to defend, and Napoleon managed to find the gap between the First and Second Army, and began to head for Vitebsk. Bagration had a close call when he was almost surrounded. The Russian troops decided to retreat and regroup in Smolensk.

   Unfortunately, on the way to Vitebsk, there were still no signs of a battle, while getting farther and farther from the base. The supply train was out of its range, and the wagons were not holding up to the rough country side. So many supplies and repair materials had been abandoned that there weren't any forges or nails to shoe the horses. Because of this, already half of the horses were unuseable. The infantry weren't doing so well either: Disorder and dysentery were beginning to appear.

   Now in Vitebsk, Napoleon had to decide whether to stay and wait for an attack, or to continue on and seek a battle. He of course, preferred the second option. Two things led him to choose to continue: 1. A Russian officer prisoner said that the Russians were preparing to stand at Smolensk. 2. A skirmish on August 8 between French cavalry and Russian Cossacks convinced him that the Russians had decided to fight.

 Barclay De Tolly was held under a lot of pressure from the senior officers to stop retreating. Finally, Barclay de Tolly agreed to counter-attack Napoleon with the First and Second Armies from Smolensk. The tension between Bagration and De Tolli was high, thereby creating coordination problems.

   After the skirmish in Smolensk, the French found lots of supplies there, so Napoleon ordered his troops to stop and rest. Shortly after, Murat and his advance guard gave an unconfirmed report that the Russians were making a stand. Napoleon was again drawn into action to go take his victory.

   On August 29, the Russian Army met up with Kutusov and his troops west of Gzhatsk. The Russian Army continued retreating until September 3 when they reached a good defensive position in Borodino. Now that their numbers were increased to match Napoleon's, Kutusov decided that the battle could no longer be postponed.

text source: Glover