At last the terrible war of 1812 broke out, and the French armies passed the Niemen. Russia was invaded; the battles of Moscowa and the Mojaisk drove back the armies of Alexander towards the sacred city of Moscow, and the ancient capital was reduced to ashes. During the whole of this campaign Pozzo di Borgo remained in London, and his influence was of service in promoting the union between Alexander and the English cabinet; he did not join the army of the Czar, because a revolution had taken place in the ideas of the cabinet of St. Petersburg. The fact was, that when Alexander found his finest provinces invaded, and the murderous war which was desolating his territory, he summoned to his assistance the old Russian spirit and the ancient traditions of the country; the banner of St. Nicholas was unfurled, the churches resounded with prayers and calls to arms against the invader, and the Czar placed himself at the head of the army: but this popular appeal had precisely the effect of rousing the national spirit against foreigners. Ever since the time of Peter the Great, the ideas of civilisation had favoured in Russia the influence of the Italians, the Germans, and the French, who filled many important military situations, and were raised to the first dignities of the state; and the old Russian families naturally entertained a jealous feeling regarding this influence. This colony of courtiers offended their pride, and interfered with their interests; therefore, when Alexander had occasion to invoke the shades of his country at the foot of the Kremlin, and to rouse the devotion of the Muscovite nobility, who lived among their serfs in the central provinces, he was obliged to sacrifice the strangers to their prejudices. Pozzo di Borgo was not recalled till the close of the campaign, when the impulse had ceased to be entirely Russian, but had become more eccentric and inclined towards Poland and Prussia, and he returned through Sweden just at the time when Bernadotte was becoming more nearly connected with England, and, without however openly committing himself, had begun to lend a favourable ear to the overtures of the court of London. The Russian councillor was commissioned to encourage the inclination of Bernadotte, and to strive to forward a decision which would afford his sovereign a new opportunity of taking vengeance for the invasion of his country by the Emperor of the French. This was the first beginning of his intimacy with the Crown Prince of Sweden.