Which 1806 decree established the Continental System against Britain?

The 1806 decree that established Napoleon’s Continental System against Britain was the Berlin Decree.

Napoleon issued it in Berlin on November 21, 1806, after France defeated Prussia and occupied the Prussian capital. It declared the British Isles under blockade and prohibited French-controlled or allied territories from trading with Britain. British goods were to be seized, and British subjects found in French-held territory could be treated as prisoners of war.

The decree was an economic response to Britain’s naval blockade of the French coast. Napoleon hoped that cutting Britain off from European markets would damage its commerce and force it to make peace. In practice, the system was difficult to enforce across Europe and encouraged smuggling.

A common mix-up is the Milan Decree, issued in 1807. It reinforced and extended the earlier policy, especially against neutral ships that complied with British regulations; it did not initiate the Continental System. The Berlin Decree therefore remains the canonical answer.