however, on 31 august 1939, the troops were once more called to action for the following day, 1 september 1939, and this time the order went through as planned, and world war ii began in europe. this decision was given out the day before in a document signed personally by adolf hitler, titled "weisung nr. 1 für die kriegsführung" ('directive no. 1 for the conduct of the war'), justifying the war as the result of the exhaustion of political means and setting the day and time of attack to 4:45 in the morning of 1 september 1939.