A change in public opinion came when Napoleon, suspecting the loyalty to him of his former marshal, heaped insults upon Sweden, and finally, in the beginning of 1812, invaded Swedish Pomerania, intending by this act to frighten the Swedes into submission. Instead, he exasperated them and lost their friendship, thus giving Bernadotte the opportunity he had awaited. "Napoleon has himself thrown down the gauntlet, and I will take it up," he said, and at once began to prepare for the struggle which he foresaw. With the incitement of the invasion of Pomerania the Crown Prince Charles John--Prince Karl Johan, as the Swedes called him--began active preparations for war. The army was largely increased, new levies being raised and arms and equipment purchased, while alliances were made with foreign powers. It came as a surprise to the Swedes when the fact leaked out that it was not against Russia, but against France, that these warlike movements were being made. Napoleon now, seeing the state of affairs his injudicious act had brought about, sought to gain the friendship of Sweden, making alluring offers to his late marshal. His change of front came too late. Bernadotte had no confidence in him and came into closer relations with his enemies, encouraging the perplexed Alexander to a firm resistance against the French emperor in the great invasion threatened. Everyone knows the disastrous end of this invasion. When Napoleon was marching on Moscow Alexander and Charles John met at Abo and a treaty was formed in which Sweden was promised recompense for the loss of Finland in the acquisition of Norway, while a friendship sprang up between the two which lasted till the end of their lives. Events now moved rapidly. The Corsican conqueror entered Moscow. It was burned and he was forced to retreat. A terrible winter and hostile forces destroyed the Grand Army, only a handful of which escaped. Then came the death struggle in Germany of the greatest soldier in modern history. On every side his enemies rose against him and in the spring of 1813 Bernadotte joined them with an army of thirty thousand Swedes. This army took part in the several battles that followed, and made its mark especially at Dennewitz, where Marshal Ney commanded the French. Bernadotte thought that the Prussians should bear the brunt of this battle, since Berlin was threatened, and for this reason he held the Swedes in reserve. But when the right wing of the Prussians was broken, Ney cheering his soldiers by shouting, "My children, the victory is ours!" he deemed it time to take a hand, and ordered General Cardell, his artillery chief, to support the Prussians. Cardell won the day by a brilliant stratagem. He ordered the caissons into line with the guns and deployed his regiments so that they bore the appearance of a division of cavalry, the mounted artillerists bearing down upon the French at a gallop, with drawn swords.