Weidenfeld and Nicolson, 1975 Ultimatum of 1939 A revised and less favorable proposal came in the form of an ultimatum delivered by the Nazis in late August, after the orders had already been given to attack Poland on September 1, 1939. Nevertheless, at midnight on August 29, von Ribbentrop handed British Ambassador Sir Neville Henderson a list of terms that would allegedly ensure peace in regard to Poland. Danzig was to return to Germany and there was to be a plebiscite in the Polish Corridor; Poles who had been born or had settled there since 1919 would have no vote, while all Germans born but not living there would. An exchange of minority populations between the two countries was proposed. If Poland accepted these terms, Germany would agree to the British offer of an international guarantee, which would include the Soviet Union. A Polish plenipotentiary, with full powers, was to arrive in Berlin and accept these terms by noon the next day. The British Cabinet viewed the terms as "reasonable," except the demand for a Polish Plenipotentiary, which was seen as similar to Czechoslovak President Emil Hácha accepting Hitler's terms in mid-March 1939. When Ambassador Józef Lipski went to see Ribbentrop on August 30, he was presented with Hitler’s demands. However, he did not have the full power to sign and Ribbentrop ended the meeting. News was then broadcast that Poland had rejected Germany's offer. Nazi German invasion – end of the corridor On September 1, 1939, Germany invaded Poland. The German Fourth Army defeated the Polish Pomorze Army, which had been tasked with the defense of this region, and captured the corridor during the Battle of Tuchola Forest by September 5. The corridor was subsequently directly annexed by Germany until it was recaptured by the Red Army at the end of the war. Other notable battles took place at Westerplatte, the Polish post office in Danzig, Oksywie, and Hel. Ethnic composition Most of the area was inhabited by Poles, Germans, and Kashubians. The census of 1910 showed that there were 528,000 Poles (including West Slavic Kashubians) compared to 385,000 Germans in the region. The census included German soldiers stationed in the area as well as public officials sent to administer the area. Since 1886, a Settlement Commission was set up by Prussia to enforce German settlement while at the same time Poles, Jews and Germans migrated west during the