Following the outbreak of war between Germany and the Allies in September 1939, Adolf Hitler ordered the German Navy to begin commerce raiding against Allied merchant traffic. Hitler nevertheless delayed issuing the order until it became clear that Britain would not countenance a peace treaty following the conquest of Poland. The Admiral Graf Spee was instructed to strictly adhere to prize rules, which required raiders to stop and search ships for contraband before sinking them, and to ensure that their crews are safely evacuated.