Rommel was promoted to "Generalmajor" on 23 August 1939 and assigned as commander of the "Führerbegleitbatallion", tasked with guarding Hitler and his field headquarters during the invasion of Poland, which began on 1 September. According to Remy, Rommel's private letters at this time show that he did not understand Hitler's true nature and intentions, as he quickly went from predicting a swift peaceful settlement of tensions to approving Hitler's reaction ("bombs will be retaliated with bombs") to the Gleiwitz incident (a false flag operation staged by Hitler and used as a pretext for the invasion). Hitler took a personal interest in the campaign, often moving close to the front in the "Führersonderzug" (headquarters train). Rommel attended Hitler's daily war briefings and accompanied him everywhere, making use of the opportunity to observe first-hand the use of tanks and other motorized units. On 26 September Rommel returned to Berlin to set up a new headquarters for his unit in the Reich Chancellery. Rommel briefly returned to occupied Warsaw on 5 October in order to prepare for the German victory parade. In a letter to his wife he claimed after several days of blockade of movement and exposure to danger in the ruined city, the inhabitants were now rescued.