Napoleon chose to invade Russia for numerous reasons, however one of the most significant was Russia’s failure to co-operate with the Continental System. Designed to starve Britain of trade, and to cause the collapse of its economy, the Continental System forbade the import of British goods into any European countries allied to or dependent on France, and placed a general trade embargo on exports to Britain. As Russia had become France’s ally by signing the Treaty of Tilsit in 1807, it was forced to comply, however, the Russian economy was generally weak in manufacturing and rich in resources, and therefore became largely dependent on trade with countries of the Continental System to sustain itself. By 1810, declining trade to these countries and its subsequent impact on the faltering Russian economy inspired the Tsar, Alexander I, to withdraw Russia from the Continental System, and open trading with Britain, mainly exporting grain and porcelain, which found willing buyers in British markets. The trade in grain allowed Britain to keep its sailors and the allied armies it supported fed, especially during the Peninsular Campaign (1808-1814), which was becoming Napoleon’s ‘Spanish Ulcer’, robbing him of the resources and men to enact campaigns elsewhere, whilst generally draining French morale.