Meanwhile the main forces of the allies were concentrated for a campaign against Napoleon in Champagne. Of the three armies which had combined at Leipzig the Austro-Russian army under Schwarzenberg made its way through Switzerland, Alsace, and Franche-Comté, while Blücher's army of Prussians and Russians passed through the region which afterwards became the Rhine province and Lorraine. The two armies united in the neighbourhood of Brienne in Champagne. Bernadotte's army did not as a whole take part in the campaign; but a portion of it, consisting of Russians under Wittgenstein and Prussians under Bülow, was engaged in the conquest of Belgium and was able to invade France itself later in the year. Schwarzenberg's army was accompanied by the Emperors of Russia and Austria, the King of Prussia, and the leading European diplomatists, including Castlereagh. From the outset there was a marked difference between the Austrian and Russian policies. Metternich was content with reducing France to the natural frontiers already offered to her, and aimed merely at compelling Napoleon to recognise the _fait accompli_ in Germany, and to evacuate Italy and Spain. He was therefore in favour of slow advances and of giving Napoleon every opportunity for coming to terms. The tsar, on the other hand, wished to reduce France to her ancient limits, and was anxious to enter Paris as a conqueror. He also excited Austrian jealousy by his scheme of annexing what had been Prussian Poland, and compensating Prussia with Saxony. Castlereagh and the Prussian minister, Hardenberg, supported the tsar's policy towards France, but without sharing his ardour.