Battle of The Netherlands - The Oster Affair

The Oster Affair

The German population and troops generally disliked the idea of violating Dutch neutrality. The German propaganda therefore justified the invasion as a reaction to an Entente attempt to occupy the Low Countries. Some German officers had an aversion against the Nazi regime and were also uneasy about the invasion. One of them, Colonel Hans Oster, an Abwehr (German intelligence) officer, began in March 1939 to pass along information to his friend, the Dutch military attaché in Berlin Major Gijsbertus J. Sas. This information included the attack date of Fall Gelb. Sas informed the Allies via other military attachés. However, both the Dutch government and other nations became insensitive to the series of false alarms, as the date would be changed many times, because the attack was postponed to wait for favourable weather conditions. Sas' correct prediction of the date of the attack on Denmark and Norway went largely unheeded. Though he indicated a German armoured division would try to attack the Fortress Holland from North Brabant and that there was a plan to capture the Queen, the Dutch defensive strategy was not adapted and it was not understood these were elements of a larger scheme. On 4 May Sas again warned that an attack was imminent; this time it coincided with a warning from Pope Pius XII. When in the evening of 9 May Oster again phoned his friend saying just "Tomorrow, at dawn", the Dutch troops were put on alert. Oster was a leading figure of the German resistance from 1938 to 1943, and was one of those hanged after the 20 July 1944 bomb plot to assassinate Hitler.