As the 3rd & 2nd Brigades of the AIF 1st Division were marching to relieve the AIF 3rd Division in the Baizieux and Corbie areas of the Somme, a disturbing message was received at its headquarters that the Germans had attacked the previously quiet sector of the front held by the Portuguese troops between the La Basse canal and Bois Grenier and had penetrated four miles on a ten mile front. They later heard that the front had been extended north of Armentieres which the I Anzac Corps had just left. At 7.30pm came a message countermanding all moves previously laid down for the division and warning it to be prepared to entrain next day for the north. Unbeknown to the Australians at this stage, the Germans had on 9th April 1918 launched their next phase in the Kaiserschlacht – Operation Georgette , or the Battle of the Lys – with with the thrust towards the vital British rail-head at Hazebrouck and gateway to the Channel ports of Calais, Boulogne and Dunkirk. The belts of wire entanglements and concrete strong-points built so diligently by the Australians during the previous winter were overrun in just a few hours.