13 March 1916 – Fifth Isonzo

Field Marshall Luigi Cadorna was already planning an offensive for the spring when the Germans began their massive offensive at Verdun. Invoking strategic agreements made at Chantilly last December, French supreme commander Joseph Joffre has asked Cadorna to strike a blow against the Austro-Hungarian Empire in hopes of drawing German strength away from France. Never enthusiastic about his allies, Cadorna has nevertheless moved up his timetable by a few weeks for fear that a German victory at Verdun might well undo Italy’s plans in the Alps.

His battle plan is a clear example of applied ‘attrition doctrine.’ Rather than draw up a detailed schedule for complete victory, Cadorna hopes to weaken Austria with a series of attacks on limited objectives. Issuing vaguely-worded orders, Cadorna allows his subordinates to choose their own targets as long as they conquer the towns of Tolmino and Gorizia (see above photo, taken from the Italian side facing south). Commanding the 2nd Army, General Pietro Frugoni attacks the bridgehead at Tolmino, while the Duke of Aosta aims to capture San Michele by attacking at Gorizia and the Carso Plateau. Altogether, they have 29 divisions — about 350 battalions — and almost 1,400 artillery guns. The latter have spent the winter being repositioned towards the front so they can reach further behind Austrian lines.


Italian officers behind a parapet during the Fifth Battle of the Isonzo. Note the barbed wire on the side facing the enemy. The man at center appears to be Cadorna

The unit they are attacking has been depleted all winter by the demands of other fronts. Serving under General Svetozar Boroević von Bojna, the 5th Army has lost four crack Alpine divisions redeployed to the Balkans or the Trentino. With a third of its rifle battalions and artillery gone, the formation now consists of just ten divisions, with half its 100 battalions being second-line militia units. Their shell reserves depleted, Boroević’s army is last in priority for newer, more modern weapons. Yet his position remains strong, for deep digging and the advantageous terrain make it possible to defend his sector even with limited troop strength.

He is also armed with foreknowledge, as the Italians are unable to practice strategic deception or cover their movements in a cloak of operational security. Reconnaissance has seen an increase in train traffic through communications hubs in recent weeks, while troop movements to the front have been impossible to conceal. When patrols began testing his defenses in strength a few days ago, it was a sure sign of a pending attack. Alerted to the coming storm of steel, Boroević’s men have been improving their positions at fever-pitch since the last days of February. When Cadorna’s preparatory bombardment began two days ago, they were ready.

And because Cadorna never shows the slightest hint of imagination, neither must Boroević. Predictable enemies are the best kind.

San Martino del Carso

Destruction in San Martino del Carso, a contested town on the Carso Plateau, after being captured later in the year

The barrage has lasted two whole days. As usual with Cadorna, the firing is unfocused, booming up and down the full length of the Isonzo without concentrating on specific targets. Batteries seem to smash areas instead of points, wasting much of the tremendous firepower advantage that the Italians enjoy. Today, as Cadorna’s infantry attacks are set to begin, the weather is abysmal: upriver, deep snow makes infantry advance slow and arduous; downriver, thick fog reduces visibility to near-zero. His assaults stall and fail almost as quickly as they begin.

Making just one attempt, the three attacking divisions of 2nd Army win no gains at all. There is a bit more success in the south, where 3rd army presses hard on San Martino mountain and village, but when the 2nd Division moves on the town they are thrown back with contempt by an experienced Magyar regiment counterattacking behind a barrage of tear gas. Tomorrow will be the same: units will make fumbling assaults on their objectives, fall back as fast as they have gone ‘over the top,’ and take no ground. Mount Calvario, Mount Sabotino, and the defensive line between Mount Sei Busi and Monfalcone once again prove impenetrable obstacles to the advance — as planned and executed by Boroević for almost a year running.

By the 16th of March, when a frustrated Cadorna finally calls a halt to the Fifth Battle of the Isonzo, he will have won less ground than any of his previous four offensive efforts here — and at the cost of 13,000 Italian lives.


The opening of an Austrian tunnel bunker at San Martino. Defenders waited out artillery bombardments in relative safety, then swarmed out to meet the Italians with interlocking and mutually-supporting rifle and machine gun fire