Military Operations, Italy 1915-1919

2–12 May 1915

Gorlice–Tarnów Offensive

THE THEATRE OF WAR 1

General Rohr, who was in command of the defence forces, was promised seven more divisions; but this number, owing to events elsewhere, was early in April 1915 reduced to three and a half ; and of these, one was earmarked for the Trentino and one for Pola, the great naval port 70 miles south of Trieste. Arrangements had been made by Field Marshal Conrad von Hétzendorf, the Austrian Chief of the General Staff, for a combined full-dress offensive against the Russians, now known as the Battle of Gorlice-Tarnow of Ist May 1915. Although at least twenty divisions (ten of them German) were considered necessary by Conrad to hold the attack of the 35 Italian divisions, after a joint German-

THE THEATRE OF WAR 1

Austrian Conference on 24th April, it was decided to let the offensive against Russia proceed, with 13 Austrian and 9 German divisions (Austrian Thivd and Fourth Armies, with the German Eleventh between them), and send help to the Italian front as soon as possible. Meanwhile General Rohr was to do his best to hold in check the Italian attack which seemed probable in the Isonzo area. The Archduke Eugen was appointed to command the troops against Italy. On 11th May one Austrian division was sent to the Isonzo from Serbia, and on 21st May, the Gorlice-Tarnow offensive having succeeded beyond all hopes, the Austrian VJJ Corps (3 divisions), earlier in reserve of the Austrian Third Army in Galicia, was entrained for the same front. Then rumours of the Pact of London reached Vienna, and in consequence eight or more divisions (3 from Galicia and 5 from the Balkans, where they were replaced by 3 German) were placed under orders to concentrate by 5th June around Marburg (in Styria, about 200 miles north-east of Trieste, with rail communication to that city), to form a new Fifth Army, under General Boroevic von Bojna Svetosar, on the © Isonzo front, General Rohr taking over the Carnia group and General Dankl the Trentino. General von Falkenhayn, the German Chief of the General Staff, was more interested in an invasion of Serbia (which took place in October, for the purpose of transporting munitions to the Turks on the Gallipoli peninsula) than in operations against Italy. He did no more than send the Alpine Corps (actually the ‘strength of a division, 13 battalions, 11 machine-gun companies and 9 batteries) to the Southern Tirol to make sure that Bavarian territory was not molested ; but it was not to cross the Italian frontier. Unable to persuade the Germans to give him help, Conrad, much against his will, was forced into the defensive. When, on 23rd May, Italy declared war on Austria-Hungary, Boroevic had seven divisions on the Isonzo front, sufficient to delay the enemy, as the defences of the sector had been well prepared, with plenty of shelters excavated in the rock. Should, however, the Italians break through, Conrad was quite ready with a plan to deal with them on their exit from the mountain region with a force of 20 divisions which could meantime have been assembled in and east of the valley of the Save.

4 June – 20 September 1916

Brusilov Offensive

PRINCIPAL EVENTS XXV

Brusilov offensive begins ; ends 17th August. ITALIAN COUNTER-OFFENSIVE IN TRENTINO begins ; ends 7th July.

AUSTRIAN TRENTINO OFFENSIVE, 1916 17

intensive bombardment, attacked on 15th May side by side on a 21-mile frontage east of the Adige, gradually extending eastward until this frontage was nearly doubled. Although the attack was not a surprise, its vigour certainly was. In the first five days the enemy advanced three to five miles, in places breaking through the Italian third line, but in general being brought to a stand before it. In the next nine days (20th-28th May) advance was made only in the centre; in the next 13 days (29th May-10th June), ground was won on the left (east) on the Asiago plateau, towards which side the battle front had been extended. During 11th to 18th June a final attempt was made to push down the valley of the Astico at the junction of the Eleventh and Third Armies. The general advance made by 10th June was from 12 miles on the left in the Asiago direction to about nine miles on the right near Mount Pasubio. The Austrians had not managed to debouch from the mountains. They were to go no farther. On 4th June, on the Eastern Front, General Brusilov, in response to Italian cries to Russia for help, had begun his offensive between the Carpathian mountains and the Pripet marshes towards Lemberg,! with the troops he had in the line. On a 50-mile front the Austrians were in flight. Conrad was now forced to beg Falkenhayn for help. At a conference between them on 8th June it was decided to stop the Tirol offensive and recall first 14 divisions and then 24 more.

AUSTRIAN TRENTINO OFFENSIVE, 1916 19

1 The Austrian casualties cannot be found, only the statement that in the two months June and July the strength of the Army fell by 346,000 men; but this figure includes the heavy losses in the Brusilov offensive (A.O.A. iv, p. 724). The Italian account does not give the number of

REFLECTIONS

offence. On the map, the strategic advantage of the shape of the common frontier seemed to be with the Austrians ; for if they could push south from the Trentino they would cut in behind the Italians standing on the Isonzo, the Tagliamento or the Piave. The difficulties, however, of the communica- tions through the Trentino prevented any decisive blow being delivered from that direction. This became evident in Conrad von Hétzendorf’s attempt in 1916, even before the Brusilov offensive forced him to desist. Similarly, the repeated Italian attempts to break into Austria from the Isonzo area achieved nothing decisive ; but in this case it was lack of heavy artillery as much as anything which handicapped the attacker. The Germans chose the Isonzo area rather than the Trentino for their decisive attack, although in that sector the paucity of railheads was bound to slow down the operations.

24 October – 19 November 1917

Battle of Caporetto

FROM THE OPENING OF HOSTILITIES UNTIL THE END OF

State of the Italian Army : The Theatre of War : The Opposing Austro-Hungarian Forces : The First Four Battles of the Isonzo : Allied Plans for 1916 and the Fifth Isonzo Battle : Italian Requests for Heavy Artillery : The Austrian Trentino Offensive : The Sixth Battle of the Isonzo (Battle of Gorizia), 6th-17th August 1916: The Autumn Offensive, 14th September-— 4th November 1916 ; The Seventh, Eighth and Ninth Battles of the Isonzo.

THE YEAR 1917 UNTIL THE EVE OF THE BATTLE OF

Plans for 1917 : Assistance to Italy Discussed : General Cadorna’s Views and the Visits to him of Generals Nivelle and Robertson : Br.-General Crowe’s Mission : Projects for Transport of Troops to Italy : Loan of Heavy Batteries to Italy : The Tenth Battle of the Isonzo (12th May-Sth June) : The Battle of Ortigara (10th June) : The Eleventh Battle of the Isonzo (The Bainsizza, 17th August—12th September) : The Austrian kK treat : Results of the Eleventh Battle.

THE TWELFTH BATTLE OF THE ISONZO. THE BATTLE OF

CHAPTER IV PAGE THE TWELFTH BATTLE OF THE ISONZO. THE BATTLE OF CAPORETTO ae ous 4 ... 40

THE ARRIVAL OF THE BRITISH AND FRENCH DIVISIONS.. 88

The Move of the XIV Corps to Italy : Lord Cavan in Italy : Decision as to the Area of Concentration : Arrival of General Sir Herbert Plumer : General Plumer’s First Report : Move of the XI Corps to Italy : Arrival of the French Contingent : Inter-Allied Con- sultations : Appointment of General Fayolle : Advance of the XIV Corps : Anglo-French Troops ordered into the Line : The End of the Caporetto Offensive.

15–23 June 1918

Second Battle of the Piave River

PRELIMINARY DISCUSSIONS ON AN ITALIAN OFFENSIVE... 242

Note: The Austrian Plans after the Battle of the Piave ... : 249

TO WHICH MOST FREQUENT REFERENCE IS MADE

A military account of the three battles of the Piave.

LIST OF BOOKS XX1

PENGOV: “ Die Wahrheit tiber die Piave Schlacht ”’. By Major- General Pengov. (Miihlau bei Innsbruck: Im Selbstverlag des Verfassers.)

DISCUSSIONS

In the latter’s plan the [sonzo Army was to cross the Piave in the Papadopoli sector, with 2 divisions attacking lower down, and the Sixth Army (less XV Corps, which was allotted to assist Conrad) was to co-operate, ‘‘ passing along “the southern foot of the Montello’’. Boroevic naturally objected to 3 cavalry divisions being taken from him for Conrad, and to 4 divisions being allotted to the general reserve, remarking that “‘ reserves in being are worthless, “only those on the field are of value”: he required a minimum of 23 to 24 divisions, and had calculated on having 30}: under the conditions of re-distribution, he would now have nothing with which to meet an emergency, which he characterized as “‘ regrettable ’’, as he considered the Piave offensive was the decisive affair. Each of the two com- manders of the Groups of Armies not unnaturally held his operation to be the vital one, whilst the High Command now looked on the offensive as a “ pincer ”’ attack in which both thrusts were of perfectly equal value. So General Arz von Straussenburg allotted 23} divisions to each, the 4 divisions in the general reserve being included in the Piave Group ; for in view of the difficulties of transportation on the mountain front, no more troops could be effectively moved and supplied there. It was pointed out by the Archduke Joseph that to make both attacks of the same strength was unwise ; for one reason alone that if both were successful their inner flanks would collide, and an accumulation of force would thus occur where it would be of no value. If either of the two thrusts was made very strong, he said, it would as it penetrated ease the task of the other. General von Arz therefore decided to make the Piave attack the main one ; but it seems that Kaiser Karl favoured Conrad’s bolder plan, and the result was a compromise.