On the Italian front, Cadorna’s 10th Battle of the Isonzo in May–June 1917 won very little ground; but his 11th, from August 17 to September 12, during which General Luigi Capello’s 2nd Army captured much of the Bainsizza Plateau (Banjška Planota), north of Gorizia, strained Austrian resistance very severely. To avert an Austrian collapse, Ludendorff decided that the Austrians must take the offensive against Italy and that he could, with difficulty, lend them six German divisions for that purpose.

The offensive was boldly planned, very ably organized, and well executed. While two Austrian armies, under General Svetozar Borojević von Bojna, attacked the eastern end of the Italians’ Venetian salient on the Bainsizza Plateau and on the low ground near the Adriatic shore, the German 14th Army, comprising the six German divisions and nine Austrian ones under Otto von Below, with Konrad Krafft von Dellmensingen as his chief of staff, on October 24, 1917, began to force its way over the barrier of the Julian Alps at the northeastern corner of the Venetian salient, with Caporetto approximately opposite the middle point of the line. The Italians, completely surprised by this thrust, which threatened their forces both to the north and to the south, fell back in confusion: Below’s van reached Udine, the former site of the Italian general headquarters, by October 28 and was on the Tagliamento River by October 31. Below’s success had far exceeded the hopes of the planners of the offensive, and the Germans could not exploit their speedy advance as effectively as they wished. Cadorna, with his centre shattered, managed by precipitate retreat to save the wings of his army and was able, by November 9, to rally his remaining 300,000 troops behind the Piave River, north of Venice. The Italians had sustained about 500,000 casualties, and 250,000 more had been taken prisoner. General Armando Diaz was then appointed commander in chief in Cadorna’s place. The Italians managed to hold the Piave front against direct assaults and against attempts to turn its left flank by an advance from the Trentino. The Italians’ defense was helped by British and French reinforcements that had been rushed to Italy when the collapse began. A conference of the military and political leaders of the Allies was held at Rapallo in November, and out of this conference there sprang the joint Supreme War Council at Versailles, and ultimately a unified military command.

Mesopotamia, summer 1916–winter 1917

The British forces in Mesopotamia, neglected hitherto and discouraged by the disaster at al-Kūt (see above Mesopotamia, 1914–April 1916), received better attention from London in the second half of 1916; and Sir Frederick Stanley Maude, who became commander in chief in August, did so much to restore their morale that by December he was ready to undertake the recapture of al-Kūt as a first step toward capturing Baghdad.

By a series of outflanking movements, the British made their way gradually and methodically up the Tigris, compelling the Turks to extend their defenses upstream. When the final blow at al-Kūt was delivered by a frontal attack on February 22, 1917, British forces were already crossing the river from the west bank behind the town; but though al-Kūt fell two days later most of the Turkish garrison extricated itself from the threatened encirclement. Unable to hold a new line on the Diyālā River, the Turkish commander, Kâzim Karabekir, evacuated Baghdad, which the British entered on March 11. In September the British position in Baghdad was definitively secured by the capture of ar-Ramādī, on the Euphrates about 60 miles to the west; and early in November the main Turkish force in Mesopotamia was driven from Tikrīt, on the Tigris midway between Baghdad and Mosul.

Maude, having within a year changed the Mesopotamian scene from one of despair to one of victory, died of cholera on November 18, 1917. His successor in command was Sir William Marshall.

Palestine, autumn 1917

Having assumed command in Egypt (see above The Egyptian frontiers, 1915–July 1917), Allenby transferred his headquarters from Cairo to the Palestinian front and devoted the summer of 1917 to preparing a serious offensive against the Turks. On the Turkish side, Falkenhayn, now in command at Aleppo, was at this time himself planning a drive into the Sinai Peninsula for the autumn, but the British were able to strike first.

The Turkish front in southern Palestine extended from Gaza, on the coast, southeastward to Abu Hureira (Tel Haror) and thence to the stronghold of Beersheba. To disguise his real intention of achieving a breakthrough at Abu Hureira, for which, however, the capture of Beersheba was obviously prerequisite, Allenby began his operation with a heavy bombardment of Gaza from October 20 onward. When Beersheba had been seized by converging movements on October 31, a feint attack on Gaza was launched next day to draw the Turkish reserves thither. Then, the main attack, delivered on November 6, broke through the weakened defenses at Abu Hureira and into the plain of Philistia. Falkenhayn had attempted a counterstroke at Beersheba, but the collapse of the Turkish centre necessitated a general retreat. By November 14 the Turkish forces were split in two divergent groups, the port of Jaffa was taken, and Allenby wheeled his main force to the right for an advance inland on Jerusalem. On December 9 the British occupied Jerusalem.