The Collaborative International Dictionary
Continental system \Continental system\ (Hist.) The system of commercial blockade aiming to exclude England from commerce with the Continent instituted by the
Berlin decree, which Napoleon I. issued from Berlin Nov. 21, 1806, declaring the British Isles to be in a state of blockade, and British subjects, property, and merchandise subject to capture, and excluding British ships from all parts of Europe under French dominion. The retaliatory measures of England were followed by the
Milan decree, issued by Napoleon from Milan Dec. 17, 1807, imposing further restrictions, and declaring every ship going to or from a port of England or her colonies to be lawful prize.
Wikipedia
The Milan Decree was issued on December 17, 1807 by Napoleon I of France to enforce the Berlin Decree of 1806 which had initiated the Continental System. This system was the basis for his plan to defeat the British by waging economic warfare. The Milan Decree stated that no European country was to trade with the United Kingdom.