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. Its army, the Italian official history explains, had been built up since 1859 around the old Sardinian army, absorbing the troops of Tuscany and Emilia, soldiers of the dissolved army of the Two Sicilies and officers of Garibaldi's southern army. In its first years it fought brigandage in the south, and the same history judges that this did more harm than good to tactical training and discipline, above all for officers whom no real experience of regular war had prepared for command.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, relying on the fortress quadrilateral of Verona, Peschiera, Mantua and Legnago, and would not seek battle. 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. Meanwhile General Pianell, whose 2nd Division had been left west of the Mincio to watch Peschiera, sent the Aosta brigade across the river on his own initiative. It struck the flank of the Austrian reserve division, and in this attack, as Treccani records, Italian bersaglieri destroyed an Austrian battalion that lost 9 officers and 726 men.⁶

The fight for the heights

In the center two Austrian brigades attacked the Sardinian grenadiers on Monte Croce at 9 a.m. and were thrown back twice, losing, by Treccani's figures, about a thousand men and 80 officers. Fresh Austrian brigades then took the heights of Custoza at 10 a.m., and General Brignone's grenadier division fell back, though groups of grenadiers held on in the village. At 10:30 a.m. General Giuseppe Govone's 9th Division was ordered up to 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 range 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; by 10:30 a.m., the French writer Charles de Mazade recorded in 1867, he was already leaving to prepare a retreat toward Goito.⁸

The archduke's last effort

After a lull at 3:30 p.m., 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 Austrians did not pursue: their official history says that men and horses were exhausted by the heat, the lack of water and the strain of the fighting, that almost every unit had been in action, and that a pursuit was therefore out of the question.⁹

A defeat of the commanders

Losses were heavy on both sides. The Austrian official history puts the Austrian loss at 7,956 men, 1,500 of them taken prisoner, some wounded, and the Italian loss at 8,145, including more than 4,000 unwounded prisoners. The Italian official history counts 7,403 Italian officers and men killed, wounded, taken prisoner or missing, and gives the Austrian loss as 7,956. 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: a few days later the army was able to resume 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