A number of factors explain the French retreat. Among them should not be forgotten the outstanding performance of the Russian light cavalry and Cossacks. In his journal Chernyshev commented that in previous wars ‘partisan’ units had raided behind enemy lines to capture supply trains and take prisoners in order to gather intelligence. They had also attacked small enemy units. He added that in the 1813 campaign his own partisans did much more than this. For considerable periods they had cut enemy operational lines and stopped all movement and communication. Operating sometimes hundreds of kilometres ahead of the main Russian forces, they had created a complete fog around enemy commanders and in some cases had actually forced fundamental changes in enemy plans. With typical modesty, Chernyshev concluded that the commander of a ‘flying detachment’ needed great energy, presence of mind, prudence and ability to grasp situations quickly. Chernyshev had a penchant for self-advertisement and self-promotion worthy of Nelson. To do him justice, he also had Nelson’s boldness, tactical skill, strategic insight and capacity for leadership.26
Just five days before the fall of Berlin Frederick William finally buried his doubts and consented to the treaty of alliance with Russia. An officer on Kutuzov’s staff wrote that ‘in our negotiations with them [i.e. the Prussians] the news we often received about the successes of our advance guards which were already approaching the Elbe gave us great weight’. Nevertheless, negotiations were difficult almost to the end. The main reason for this was disagreement on the fate of Poland. Prussia had been a key beneficiary of the Polish partitions. It wanted back the Polish lands which Napoleon had forced it to concede at Tilsit, and argued that without this territory Prussia could not possess the strength or security essential for a great power. On the other hand, the events of 1812 had further confirmed Alexander in his belief that the only way to square the demands of Polish nationhood and Russian security was to unite as many Poles as possible in an autonomous kingdom whose ruler would also be the Russian monarch. At a time when Russia was expending huge amounts of blood and money to restore large territories to Austria and Prussia, and when Britain had made a clean sweep of the French and Dutch colonial empires, the emperor no doubt also felt that his empire should have some reward for his efforts.27
Baron vom Stein helped to smooth over the difficulties by travelling to Breslau to win over Frederick William. Stein himself disliked Alexander’s plans for Poland, which he thought were dangerous for Russian internal stability and a threat to Austrian and Prussian security. He also wondered whether the Poles, ‘with their serfs and their Jews’, were capable of self-government. But Stein knew that on this issue Alexander was adamant and he helped to broker a Russo-Prussian compromise.
Russia would guarantee all existing Prussian possessions and it would ensure that East Prussia and Silesia were linked by a substantial and strategically defensible band of territory taken from the Duchy of Warsaw. The Russians also promised that they would commit all their strength to the war in Germany and would not make peace until Prussia was restored to the same level of power, territory and population as it had possessed before 1806. Article I of the Treaty of Kalicz’s secret clauses promised that Prussia would be fully compensated in northern Germany for any Polish territory it lost to Russia in the east. Unlike Napoleon, the Russians could not bribe the Prussians with Hanoverian territory, since this belonged to their ally, the British king. The only likely source of compensation was therefore Saxony, whose weakening or dismemberment would go down badly in Vienna. The Treaty of Kalicz therefore in part remained strictly secret and was storing up problems for the future.
For the moment, however, it was a satisfactory basis for Russo-Prussian cooperation. The main thrust of the treaty was its commitment to restoring Prussia as a great power, above all so it could check France but also perhaps in order to balance Austrian power in Germany. On this all-important issue the Russians were just as committed as the Prussians. In addition, although the preamble to the treaty contained its share of sanctimonious hypocrisy, its call for ‘the repose and well-being of peoples exhausted by so many disturbances and so many sacrifices’ was genuine and heartfelt. Add this to the friendship which existed between Alexander and Frederick William and there are the ingredients of a strong and lasting bond between the two states. Indeed in one form or another the Russo-Prussian alliance of February 1813 was to survive until the 1890s, forming one of the most stable and enduring elements in European diplomacy.28