The Continental System or Continental Blockade (known in French as Blocus continental) was the foreign policy of Napoleon I of France in his struggle against Great Britain during the Napoleonic Wars. As a response to the naval blockade of the French coasts enacted by the British government on 16 May 1806, Napoleon issued the Berlin Decree on 21 November 1806, which brought into effect a large-scale embargo against British trade. The embargo was effective intermittently for about half the time. It ended on 11 April 1814 after Napoleon's first abdication. In terms of economic damage to Great Britain, the blockade was largely ineffective. As Napoleon realized that extensive trade was going through Spain and Russia, he invaded those two countries. His forces were tied down in Spain — in which