Battle of Custoza, 1866: Italy's defeat by Archduke Albrecht

In 1866 Italy went to war against Austria as the ally of Prussia, with the aim of invading Venetia, still held by the Habsburgs. It was the first war of the Italian Army, so named only since May 1861 and formed from the Sardinian army, the former Bourbon army of Naples, Garibaldi's volunteers and the forces of the other pre-unification states, had spent its first years fighting brigandage in the south. The Italian army's own history notes that this did little to train its generals in conventional war.²

Two armies, no plan

On paper Italy was far stronger. Treccani's Enciclopedia Italiana states that it had mobilized an army more than twice the size of the Austrian Army of the South, most of which was gathered around Verona under Archduke Albrecht. But the Italian forces were split in two: twelve divisions on the Mincio under the direct orders of La Marmora, the effective commander in chief in the name of King Victor Emmanuel II, and eight on the lower Po under General Enrico Cialdini. The two operations were not tied together by any clear agreement, and Cialdini had not yet begun to cross the Po when the battle came.³

War was declared on 20 June. La Marmora was convinced that the Austrians would stay on the defensive behind the Adige and inside the fortress quadrilateral of Verona, Peschiera, Mantua and Legnago. He neglected reconnaissance and spread his divisions over too wide a front. In fact Albrecht had moved forward. He planned to strike through the morainic hills south of Lake Garda in the direction of Valeggio and catch the Italians while they were crossing the Mincio.⁴

A march that became a battle

In the small hours of 24 June two Italian corps set off, the I under General Giacomo Durando and the III under General Morozzo della Rocca, moving fanwise toward the Adige for what La Marmora believed was a simple march. The I Corps got into trouble at once. Divisions took wrong roads and blocked each other, and the vanguard of General Sirtori's 5th Division, misled by local directions, headed toward Oliosi instead of San Rocco and ran into the Austrian V Corps, while the main body of the division marched on without a vanguard until it was fired on near the Tione stream.⁵

By 7 a.m., according to Treccani, 18,000 Italians with 48 guns were engaged on the Italian left against 32,000 Austrians with 68 guns, with no help near. General Villarey was killed leading a counterattack on Monte Cricol. A captain of the Austrian cavalry charged with about a hundred uhlans into General Cerale's 1st Division, which was still marching in column on the road, and panic spread through it. On the other side of the Mincio, the Aosta brigade crossed on its own initiative, struck the Austrian flank and, as Treccani records, destroyed an Austrian battalion that lost 9 officers and 726 men.⁶

The fight for the heights

In the center the Austrians took the village of Custoza but could not break the Sardinian grenadiers on Monte Croce, where they lost, by Treccani's figures, about a thousand men and 80 officers. Toward 11 a.m. General Giuseppe Govone's 9th Division reached the heights, and his bersaglieri, with the grenadiers of Lieutenant Colonel Boni, drove the Austrians back out of Custoza.⁷

The Italians still had the means to win. Around Villafranca, within sound of the guns, Della Rocca kept 36 battalions and 30 squadrons idle. Govone and General Cugia begged him to send them up, and later Prince Umberto and General Nino Bixio asked to march to the fighting, but Della Rocca had received no new orders and would not move troops he had been told to keep at Villafranca. La Marmora gave no orders for hours. Treccani says he busied himself with small details that belonged to junior officers and then wandered behind the firing line, so that he ended up absent from the battle he was supposed to direct; the army's account has him watching the remnants of two beaten divisions pass through Valeggio around noon and riding off to secure the crossing at Goito.⁸

The archduke's last effort

After a lull in the afternoon heat, Albrecht prepared what the Austrian official report called a supreme effort, launched at 5 p.m. against Govone's division on the Belvedere height, which had been fighting for seven hours. The defenders were overwhelmed. Della Rocca ordered a general retreat, and the last Italian troops, Bixio's division, left the Villafranca plain at 9.30 p.m.. The exhausted Austrians did not pursue, and, as the Italian army's history notes, that evening they were not yet sure they had won.⁹

A defeat of the commanders

The sources do not give reliable totals for the dead and wounded, but the partial figures show how hard the fighting was on both sides. Treccani's verdict is that Custoza was not a defeat of the Italian soldiers, who fought bravely, but a painful lesson in the failings of the highest commands, and that strategically it was not decisive: within days the army could have resumed the offensive. The 20 days lost before the invasion of Venetia, however, it argues, meant a late arrival in eastern Friuli, the displeasure of Prussia and the border that weighed on Italy until 1918.¹⁰