Napoleon's determination to implement the Continental System had led him to embark on the Peninsular Campaign in a further extension of the French Wars. Although the attempt to conquer Spain was failing, Napoleon set about a greater task: the conquest of Russia. One reason for this was that Britain had become involved in a war with America and Napoleon was convinced that Britain was on the verge of collapse, provided that the blockade of trade with Britain was carried out. However, the Czar was making a big hole in the plan. The interview at Erfurt had merely checked the process of disillusionment which had been going on in Alexander's mind ever since Tilsit. There had always been a strong anti-Bonaparte party at his Court, headed by the Czar's mother; and its influence was strengthened during the next few years. For instance
Napoleon would not give definite assurances that he would not turn the Grand Duchy of Warsaw into a Kingdom of Poland
when Napoleon annexed northern Germany in 1811 he had dethroned the Duke of Oldenburg, the Czar's uncle, with insultingly offhand talk of compensations elsewhere
the Czar was angry to discover the depth of Napoleon's opposition to Russia acquiring Constantinople in the war which Alexander had just begun with Turkey.
The main trouble was over the Continental System. The stoppage of trade with England meant the ruin of Russian commerce, and therefore of the Czar's revenues; also of the corn-growing on which the Russian nobles depended for their own incomes. Alexander grew slacker and slacker in the enforcement of the Decrees, and Napoleon's protests grew more and more heated. In 1810 the Czar forbade the importation of a number of luxury articles, such as wines and lace, most of which came from France, in order to redress his trade-balance. A year later he openly admitted British shipping to his ports.
