First Battle of the Isonzo

The First Battle of the Isonzo was fought between the Armies of Italy and Austria-Hungary on the Italian Front in World War I, between 23 June and 7 July 1915.

First Battle of the Isonzo
Part of the Italian Front (World War I)
Eleven Battles of the Isonzo June 1915 — September 1917
Date 23 June – 7 July 1915 Location Isonzo river, north-west Slovenia from the mountain Krn to the Gulf of Trieste Result Limited Italian advance
Belligerents
Kingdom of Italy	Austria-Hungary
Commanders and leaders
Luigi Cadorna (Chief of Staff of the Italian Army) Pietro Frugoni (Commander of Second Army) Emanuele Filiberto di Savoia (Commander of Third Army)	Archduke Friedrich (Supreme Commander of the Austro-Hungarian Army) Franz Conrad von Hötzendorf (Chief of the General Staff) Archduke Eugen of Austria-Teschen (Commander of Southwest Front) Svetozar Boroević von Bojna (Commander of Fifth Army) Géza Lukachich von Somorja (Commander of 5th Mountain Brigade) Guido Novak von Arienti (Commander of 1st Mountain Brigade)
Strength
225,000: (18 divisions 252 battalions 111 cavalry squadrons 700 guns)	115,000: (8 divisions 84 battalions 13 cavalry squadrons 356 guns)
Casualties and losses
15,000[1]	10,000[1]

The aim of the Italian Army was to drive the Austrians away from its defensive positions along the Isonzo (Soča) and on the nearby mountains.

Although the Italians enjoyed a 2:1 numeric superiority, their offensive failed because the Italian commander, Luigi Cadorna, employed frontal assaults after impressive (but short) artillery barrages. The Austro-Hungarians had the advantage of fighting from uphill positions barricaded with barbed wire which were able to easily resist the Italian assault.

The Italians had some early successes. They partially took Monte Nero (Monte Krn), took Monte Colowrat, and captured the heights around Plezzo. However, they were unable to dislodge the Austro-Hungarian troops from the high ground between Tolmino and the Isonzo, which would later form a launching off point for the Caporetto Offensive. The heaviest fighting occurred around Gorizia. In addition to the natural defenses of the river and mountains, bastions were created at Oslavia and Podgora. The fighting at Gorizia consisted of street-by-street urban combat interspersed with artillery fire. Italian troops, such as the Italian Re and Casale Brigades, were able to advance as far as the suburbs but could get no further and were driven back. They made small footholds at Sagrado and Redipuglia on the Karst Plateau south of Gorizia but were unable to do much else.

On the Austrian-Hungarian side two commanders distinguished themselves: Major General Géza Lukachich von Somorja, commander of the 5th Mountain Brigade, who retook Redipuglia, and Major General Novak von Arienti who retook Hill 383 (overlooking Plave) with his 1st Mountain Brigade.

Early in July the commander of the Austro-Hungarian Fifth Army, General Svetozar Boroević, received two reinforcement divisions, which put an end to the Italian efforts at breaking through the Austro-Hungarian lines.

The final Italian gains were minimal: in the northern sector, they conquered the heights over Bovec (Mount Kanin); in the southern sector, they conquered the westernmost ridges of the Kras plateau near Fogliano Redipuglia and Monfalcone.