Second Custoza: Opening the Battle
By Mike Bennighof, Ph.D.
February 2006

Austria’s 1866 war with Prussia and Italy would be a military disaster for the monarchy, driving it out of its powerful positions in both Germany and Italy. While the Austrian navy could take pride in its performance, the army had only one clear victory to which it could point: Southern Army’s crushing defeat of the Italians at Custoza on 24 June. “It was not just an episode of military history,” German nationalist historian Heinrich Friedjung wrote of the battle, “it was the proof that Austria could still assert herself as a great power, despite the loss of her hegemony in Germany and Italy.”

The Second Battle of Custoza is one of the battles featured in our Classic Wargames proposal, Battles of 1866. While one of the most violent clashes of this period, it’s little known in the United States, home to most of our customers, so we have an overview of the battle starting today, in multiple installments.

Radetzky’s heirs. Ludwig von Benedek (seated, left) and the Southern Army staff, 1863. John stands at center, Maroicic to his right stares into space.

La Marmora's Plan

Austrian leaders had expected an Italian invasion since the end of their last war in the region seven years before. Vienna issued mobilization orders for Southern Army on 21 April 1866, right after Prussia and Italy signed an offensive alliance against Austria, with Prussia to decide when war began.

On 14 June Prussia declared the German Confederation dissolved and invaded Hesse-Kassel and Hannover; four days later Prussia declared war on Austria. On 20 June the Italians informed Austrian outposts that war would begin on the 23rd.

Southern Army had an excellent staff organization, at least by the Austrian Army’s standards. Chief of staff Franz Freiherr von John had a very high reputation and would later serve as army chief of staff and as Austria-Hungary’s war minister. The officers at army headquarters in Verona saw themselves as the heirs to Radetzky, and went to war with great confidence despite being outnumbered by at least three to one. One factor weighing against the confidence was the army’s new commander; Archduke Albrecht had little combat experience.

Custoza area topography. The Autostrada did not exist in 1866.

Across the border, the Italian leadership had much less confidence. Presented with two options to invade Austrian territory, the Italians chose both, dividing their forces between a thrust across the Mincio River, aimed at Verona, and one across the lower Po aimed at Venice.

Alfonso la Marmora, accompanied by King Vottorio Emanuele himself, would lead the march on Verona. Italian intelligence indicated that “the Austrian campaign plan is absolutely defensive. They will remain in their fortresses without defending the countryside and will avoid battle.”

The fortresses on which the Italians expected the Austrians to rely were the famed works of the “Quadrilateral.” Two huge modern fortresses anchored the position, Verona and Mantova, each capable of sheltering an entire field army. Two smaller but potent works at Peschiera and Legnano completed the district.

Each fortress lay about a half day’s march from two others — close enough that reinforcemertns from two others could fall on the rear of a beisieging enemy army, but far enough away to make it difficult to impossible for anything short of a huge force to screen more than one of these threats. To the north lay the Alps and Lake Garda, protected by a powerful squadron of armored, screw-driven gunboats. To the south lay the swamps of the lower Po basin. Any invader hoping to reach Venice and the Austrian heartland beyond would have to somehow neutralize the Quadrilateral or risk its lines of communication.

Southern Army had at most 70,000 men available for field action; the Italians put 220,000 into their two field armies. La Marmora’s force (unofficially called the “Army of the Mincio”) nominally brought about 140,000 onto the Custoza battlefield; but so many Italian divisions saw little or no action that at the key points the Austrians usually had local numerical superiority.

La Marmora’s campaign plan centered on the largest and most exposed of the fortresses, Mantova. With Southern Army believed to be well east of Verona, two of the three Italian corps would occupy a line between Peschiera and Verona, to stop Southern Army from interfering with the siege. These would have numerical superiority (Southern Army was believed, rather accurately, to contain about 50,000 front-line troops), and a defensive mission, and so should be able to hold off the Austrians fairly easily while the remaining corps and the Italian siege train reduced Mantova. It was the same plan laid out by the king’s father during the 1848 war that resulted in the First Battle of Custoza, but would be undertaken with a much greater superiority in numbers.

Austria's Reserves

One of the very few photographs of the battle. Bersaglieri, probably from Pianell’s 2nd Infantry Division, gather to enter battle.

Italian cavalry patrols reported no Austrians within the open ground between the fortresses, but could not locate Southern Army. The Italians began crossing the Mincio on the 23rd, not expecting to meet resistance. All of the Italian crossings took place under the eyes of Austrian cavalry scouts; by evening Southern Army headquarters had a good idea of Italian positions and goals.

Thought to be far to the east, Southern Army was instead camped in and around Verona. Albrecht left planning to John, who decided on a dawn attack on the Italians, hoping to catch them in march order and relying on the densely cultivated terrain to screen Southern Army’s approach.

The Austrian generals held a council of war on the afternoon of the 23rd, studied the scouting reports and endorsed the plan. Southern Army’s Reserve Division and V Corps moved out on the night of the 23rd, with IX and VII Corps and the cavalry reserve following at about 3 a.m. on the 24th. The Austrians hoped to scatter the Italians quickly and isolate them from their sources of supply; all the Austrian formations left their medical and supply trains within the Verona defensive works and marched light.

Of the three main attacks planned by the Austrian leadership, Albrecht's right wing would have the toughest assignment. The Reserve Division would march well to the west, then turn sharply south to seize the bridges across the Mincio. At the very least they would have to interfere with Italian lines of communication and supply between the main army around Custoza and its bases in Italian territory west of the river.The Austrians knew that the Royal Italian Army, hastily cobbled together from the armed forces of several smaller states during the preceding five years, lacked a professional supply service and relied exclusively on hired civilian wagoneers to bring up its food and ammunition. Even a minor threat to the lines of communication held great promise of hopelessly snarling the Italian advance.

The Reserve Division appears to have been chosen for this task because its camps lay the closest to the Mincio. But it was also by far the weakest of the four Austrian maneuver units. Not only did the division lack the fighting power of the regular corps, it had no engineers. Maj. Gen. Heinrich Rupprecht von Virtsolog had slightly less than one regular army brigade, reinforced by the scrapings of various fortress garrisons — two reservist “fourth” battalions (the training establishments of regular regiments), two reservist light infantry battalions, and a regiment of Grenzer border guards, not considered fit for first-line employment.

Orders for Pulz

Franz Freiherr von John, architect of the Austrian victory.

On the Reserve Division’s left flank, Maj. Gen. Gabriel Rodich’s V Corps would also march west, then turn south to occupy the heights around Sona, about five kilometers northeast of the Custoza battlefield. Afterwards, V Corps would drive the Italians southward. The twisting, tortured valley of the narrow Tione River where V Corps and the Reserve Division grappled with the Italians in 1866 had seen very little fighting during the 1848 battle, and Albrecht and John do not appear to have expected either formation to run into heavy resistance there. V Corps numbered three brigades of regulars.

In the center of the Austrian army, Feldmarschallleutnant Joseph Maroicic di Madonna del Monte’s VII Corps had the task of occupying the Italian army's attention long enough for the flanking attacks to work their way around the enemy positions. Like those of V Corps, Maroicic’s three regular brigades came close to full strength.

To the left of Maroicic lay the Austrian IX Corps. Maj. Gen. Ernst Hartung, a noted eccentric in an officer corps that prized individualism, had been one of the heroes of 1848 as a young captain, but had refused battlefield ennoblement. His troops had the shortest march of all the Austrian formations, and had orders to attack straight out of Verona in the direction of Somma Campagna. Afterwards they would be the focus of a pivot movement by the rest of the army, as the Italians were rolled up from the east.

At the far left of the Austrian line, Col. Ludwig Pulz commanded two small brigades of light cavalry, created by stripping the three line corps of their horsed component. The horsemen had already performed good service in keeping headqaurters apprised of Italian movements and shooing away the half-hearted Italian attempts to spot Austrian concentrations. For the battle, John had strict orders for Pulz — the Italian right needed to be pulled forward, toward Verona, so the Austrian right wing could cut them off from their bridgeheads. Under no circumstances were the cavalry to attack the Italians.

As is the way of careful battle plans, that’s exactly what they did as soon as they spotted the Italian infantry.

Attack of the Trani-Uhlanen on Bersaglieri squares, opening shots of the Second Battle of Custoza.

Facing the Charge

La Marmora’s three corps commanders had been chosen by the Italian king, and La Marmora tasked his most reliable general, Domenico Cucchiari of II Corps, with reducing Mantova. That left his screen in the hands of two bitter rivals, who agreed on only one thing between them: They hated Alfonso La Marmora even more than they hated each other.

Enrico Della Rocca was a personal friend of the king; in the previous December he had challenged La Marmora to a duel after a reprimand for Della Rocca’s handling of rioters in Torino. Della Rocca backed down after a direct order from the king, who said he would make it up to his friend when war came. Della Rocca took that to mean command of the main field army, and when it went to his hated rival, he burned with resentment. Command of III Corps gave him no joy, and he acted accordingly at Custoza.

Giovanni Durando had commanded the hapless papal army in the 1848 campaign and believed he deserved the major command in 1866. I Corps command did not suit him, either, and when a shell fragment nicked his finger he fled the Custoza battlefield, leaving his aide to explain that the general “feared he might develop tetanus without immediate treatment.”

Everyone hates Alfonso. The Italian commander, Alfonso la Marmora.

Durando’s I Corps held the Italian left. Durando had four divisions, and left one of them on the western bank of the Mincio to watch for any sorties from the Austrian garrison at Peschiera. More likely, he simply wanted the division commander out of the way — Giuseppe Salvator Pianell, the former Minister of War to King Francis II of Naples, may have been the most distrusted man in the Italian army. Some Italian offi-cers suspected Pianell of still serving his Bourbon master, or considered him a traitor in Austrian pay. Within a few hours he would be hailed as the savior of the Italian Army.

Meanwhile, the other three divisions on the east bank fanned out to await the Austrians, not expected for at least another day.

On the right, Della Rocca kept his divisions in close formation and did . . . nothing. He sat his horse alongside that of Crown Prince Umberto, one of his division commanders, and grumbled about his bitter fate. When a messenger from one of his divisions came begging for help later that morning, Della Rocca informed him that he had no interest in reports from “a mere lieutenant of cavalry.”

Though assigned a brigade of light cavalry to screen his troops, Della Rocca posted the horsemen behind his infantry. From there they could only watch the Austrian cavalry charge that opened the Second Battle of Custoza.