The divisions forming von Hutier's shock troops were withdrawn fairly quickly. By the end of May, only two out of the twenty-three divisions which, on March 21, had formed the XVIIIth Army, were still in line on the Moreuil-Oise front. [Illustration: BRITISH BATTERIES IN ACTION IN THE OPEN. (_Photo Imperial War Museum_).] [Illustration: BRITISH TROOPS GOING UP THE LINE NEAR ALBERT. (_Photo Imperial War Museum_).] [Illustration: AMIENS. SHELL BURSTING IN THE RUE DE BEAUVAIS. (_Photo Imperial War Museum_).] The Trench Warfare Period. From April onwards, trench warfare began again. The Allied front was reformed, consisting of a continuous line of hastily dug trenches and rapidly constructed works, held by resolute troops, whose _morale_ was intact and whose fighting spirit had never been better. Once more the heavy artillery came into requisition, for the preparatory pounding of the adversaries' positions. In April-May, sharp engagements frequently took place at certain points. On the Luce, in the region of Hangard, on the Avre, from Thennes to Mailly-Raineval, at Grivesnes, on the west bank of the Matz, and around Orvillers-Sorel. Of these, the attack of April 24, by its violence and scope, constituted a veritable offensive against Amiens. The Attack of April 24 on Villers-Bretonneux. _See sketch below._ [Illustration] The plateau of Villers-Bretonneux dominates the ground between the Avre and the Somme. It was held by the British. Slightly to the south, in Hangard Woods, close to Hill 99, was the point of junction of the Allied Armies. [Illustration: ONE OF THE 11IN. GUNS WHICH BOMBARDED AMIENS.] The enemy's main effort was made at this point, as being the weakest. The French line started at Anchin Farm, west of Moreuil, followed the western and northern outskirts of Castel, joined up with Hill 63 on the right bank of the Avre, took in Hangard, and linked up with the British near Hill 99, to the south of Hangard Wood. From this point the British line crossed the plateau between the Avre and the Somme, between Marcelcave and Villers-Bretonneux, and passed the eastern outskirts of Hamel. At 5 a.m., after an artillery preparation lasting an hour, the German infantry attacked. After a desperate struggle, the enemy captured Villers-Bretonneux. Hangard fell during the night and Cachy was threatened. The next day, a Franco-British counter-attack won back the most important part of the lost ground. Villers-Bretonneux, Hangard and Hangard Wood were recaptured and held, in spite of all the subsequent efforts of the enemy, who finally abandoned this sector in favour of Flanders. [Illustration: FRENCH TRENCHES IN THE SUBURBS OF CACHY (_see p. 59_).] Ludendorff's Opinion. In his "Memoirs", Ludendorff wrote: _The battle ended on April 4. It was a brilliant feat of arms and will always be so considered in history. What the British and French had been unable to do, we accomplished in the fourth year of the war._