The battle of Heilsberg (10 June 1807) saw the Russians defeat a series of French attacks on their fortified camp at Heilsberg, only to retreat when the French threatened to outflank the position. Four days later the Russians suffered a heavy defeat at Friedland, effectively ending the War of the Fourth Coalition.
The War of the Fourth Coalition began in August 1806 when the Prussians finally declared war on France, having stayed out of the Third Coalition. Napoleon launched a rapid invasion of Prussia and defeated their main field army in the twin battles of Auerstadt and Jena (14 October 1806). The few remaining Prussian troops, along with the King and Queen, retreated into East Prussia, where they joined up with their Russian allies. Napoleon followed, but this winter campaign ended with his first significant setback, the costly drawn battle of Eylau (8 February 1807).
In the aftermath of this battle both sides went into winter quarters. Napoleon put a great deal of effort into rebuilding his army, as well as creating a second army in Germany. At the same time he sent troops to besiege Danzig (18 March-27 May 1808), one of the last major Prussian possessions. Napoleon thought it was possible that the Russians might have attacked to try and save Danzig, but as the fall of the city became inevitable he assumed that the Russians would stay on the defensive and instead concentrated on his own plans for an offensive, which was to start on 10 June.
Napoleon had misjudged the Russian commander, General Bennigsen. On 5 June the Russians began an offensive aiming at Ney's Corps, which was potentially isolated at Güttstadt on the upper Alle River. The front line ran from north-west to south -east across the rivers Passarge and Alle. The French left was towards Danzig, their centre on the middle and upper Passarge and their right on the upper Alle. The Prussians still had a foothold on the lower Passarge. The Russians occupied the middle stretches of the Alle. Bennigsen's plan involved six columns. Some were sent west to face the French bridgeheads across the Passarge, but most were sent to try and surround Ney. The plan was over-complex, and soon fell apart. Ney was a master of the fighting retreat and he was able to escape from the trap and retreat towards the Passarge. By the end of 6 June the Russian offensive was over, and on 7 June Bennigsen ordered a retreat.
Napoleon's men were almost ready for their own offensive, and so they were able to react quickly to the Russian attack. By 8 June Napoleon's forces were on the move, heading towards Güttstadt. His aim was to prevent the Russians from retreating to Königsberg, and he hoped to catch them at Güttstadt on 9 June. Bennigsen had originally planned to make his stand there, but by the time the French arrived he had changed his mind and had retreated to Heilsberg, where there were already some strong fortifications.
During the night of 9-10 June Napoleon issued fresh orders. Davout and Mortier were sent on an long march which was meant to take them around the Russian right flank. Murat's cavalry, the three corps of Soult, Lannes and Ney, and Savary's Grenadiers, were ordered to march straight for Heilsberg, along the left bank of the Alle. Murat took the lead, followed by Soult, then Lannes, Ney and finally the Imperial Guard. Only Murat, Soult and Lannes would be involved in the fighting.
By the time the French arrived Bennigsen had put his defences in order. The 1st, 2nd, 3rd, 7th and 14th Divsions were on the right and the 4th, 5th, 6th and 8th on the left. The right wing was supported by the Cossacks and Uvarov's regular cavalry, the left by 27 squadrons of Prussian cavalry and Golitsyn's Russian cavalry. In addition there were two advance guards - Borozdin at Launau on the left bank of the river (to add confusion this was the Russian right as they faced south towards the French advance), and Bagration at Reichenberg on the right bank of the river. The Russian Imperial Guard was placed in reserve.
The fighting began early on 10 June when Murat's cavalry forced Borozdin's cavalry back from Launau to Bewernick (or Bevernick). Bennigsen responded by ordering Bagration to make a forced march to Bewernick. He crossed the Alle on pontton bridges, and reached Borozdin at around 2pm. By this point Soult had joined Murat, and between them they captured Bewernick. They were then hit in the flank by Bagration's cavalry, and were close to defeat when Savary's grenadiers arrived.
At about 3pm the French began a major infantry attack, with Legrand's division and Savary's grenadiers on the left near Bewernick, Gouvion St Cyr's division in the centre, Soult on the right and St. Hilaire in reserve. Bagration was able to stop St Cyr, but St Hilaire then sent in reinforcements and the Russians had to retreat. Bennigsen responded by sending Uvarov's cavalry into the attack, and once again the French were forced back. However the Russians had been worn out in the attack, and by late afternoon Bagration had to begin a slow retreat back into the fortifications of Heilsberg.
Murat and Soult, encouraged by Napoleon, decided to launch an attack on the Russian camp. St Cyr and St Hilaire were to attack Redoubt No.1 and Legrand was to attack Redoubt No.2 The advancing French suffered heavy losses to canister and musket fire, but the 26th Line from Legrand's division was able to take Redoubt No.2. They held onto it for about an hour under heavy pressure. The 55th Line was sent in to try and rescue them, but not units suffered very heavy losses and the Russians retook the redoubt. The Russian cavalry then went onto the offensive, and Legrand and Savary's men were forced to form squares. Once the French cavalry arrived they were able to conduct a slow retreat. This left St Cyr and St Hilaire isolated at Redoubt No.1 and they were also forced to retire.
At about 10pm Lannes arrived. He decided to launch a night attack on the Russian position, but this was badly misjudged. Verdier's Division and part of Legrand's Division attacked Redoubt No.2, but were repulsed with heavy losses. This finally ended the battle.
The French lost around 12,000 men during the day, Soult lost 8, 286 and Lannes lost 2,284 during the fighting. The Russians lost 2,000-3,000 dead and 5,000 wounded, including eight generals. Bennigsen suffered from exhaustion and collapsed on the battlefield. He was still unwell during the decisive battle of Friedland, four days later, and played little part in that battle. On the day after the battle of Heilsberg the French outflanked the Russian position and Bennigsen was forced to retreat. For the next few days both armies moved north, on opposite banks of the Alle. Late on 13 June the Russians though they had chance to defeat Lannes' isolated corps around Friedland, and began to feed men across to the left bank. This triggered the battle of Friedland (14 June 1807), which saw Napoleon finally get the victory he had been hunting for since the autumn of 1806.