Treating the subject more generally, it may be said that the limited success attained by tanks in the shell-pocked ground of the Somme and the mud of Flanders had caused the Germans and also some of our own high authorities to underrate their power and their possibilities of development. All this was suddenly changed by the battle of Cambrai, when the Germans were terrified at the easy conquest of the Hindenburg Line. They then began to build. It may be said, however, that they never really gauged {222} the value of the idea, being obsessed by the thought that no good military thing could come out of England. Thus when in the great final advance the tanks began to play an absolutely vital part they paid the usual price of blindness and arrogance, finding a weapon turned upon them for which they had no adequate shield. If any particular set of men can be said more than another to have ruined the German Empire and changed the history of the world, it is those who perfected the tank in England, and also those at the German headquarters who lacked the imagination to see its possibilities. So terrified were the Germans of tanks at the end of the war that their whole artillery was directed to knocking them out, to the very great relief of the long-suffering infantry. From this time onwards this front was the scene of continuous aggressive action on the part of the Australians, which gradually nibbled away portions of the German line, until the day came for the grand advance of August 8. One of the most successful of these was on May 19, when the village of Ville-sur-Ancre was taken by a sudden assault with 20 machine-guns and 360 prisoners. A second very sharp fight, which may be mentioned here, though it is just beyond the scope of this volume, was on July 1 and following days in the Aveluy sector, near the Ancre, where the Twelfth and Eighteenth Divisions had three bouts of attack and counter-attack, in which the 37th and 54th Brigades were heavily engaged, the honours of the action being about equally divided between the British and the Germans. {223} CHAPTER IX THE BATTLE OF THE LYS April 9-12 The Flanders front--Great German onslaught--Disaster of the Portuguese--Splendid stand at Givenchy of the Fifty-fifth Division--Hard fight of the Fortieth Division--Loss of the Lys--Desperate resistance of the Fiftieth Division--Thirty-fourth Division is drawn into the Battle--Attack in the north upon the Ninth, Nineteenth, and Twenty-fifth Divisions--British retreat--General survey of the situation.