The conflict between Germany and Poland, which was supported by Britain and France, over the Danzig territory preceded the outbreak of World War II. Beginning in October 1938, Hitler demanded that the Danzig (of Gdansk) region of Poland be ceded to Germany. This port area had been under Polish administration since the Potsdam agreement. Poland refused to cede Danzig, and in March of 1939, negotiations began between Germany and Poland. On March 30, 1939, both France and Great Britain pledged to defend Poland in the event of a German attack. By April, German troop concentrations on the Polish border began. During the summer months, Hitler made several statements about increasing German intolerance for Polish "atrocities" to German citizens in Danzig. On August 26, 1939, Germany attacked Danzig. On September 1st, Germany attacked Poland itself, and on September 3rd, Great Britain and France declared war on Germany, beginning the Second World War.