Starting in 1860, the Royal Sardinian Navy began ordering ironclad warships for what would shortly become the (Royal Navy) following the unification of Italy the next year. The first of these vessels, the two vessels of the , were small broadside ironclads ordered from France and built to French designs. These were followed by the three , all of which were built in Italy; these were originally unarmored ships that were converted while under construction. Further orders abroad followed, with the two American-built s, the four French-built s, and the British-built ram all being laid down between 1861 and 1863. Four more vessels in the first generation of Italian ironclads were laid down in Italy between 1863 and 1865, two each of the and es.

Most of these ships were constructed at the beginning of the Austro-Italian ironclad arms race and nearly all of them, with the exception of one of the Italian-built ships, had entered service in time for the Third Italian War of Independence in 1866, and they saw action at the Battle of Lissa in July 1866. There, the Italian fleet was defeated by the smaller Austrian Navy and was sunk. This led to a period of neglect for the , as naval budgets were reduced and new construction stopped. By the early 1870s, the Italian government began a new program of construction to counter what was now the Austro-Hungarian Navy, which had built several ironclads after Lissa. The naval minister Benedetto Brin was responsible for most of the vessels built as part of this program, beginning with the large and powerful , two ships that carried four massive 100-ton guns. These were followed with the two s, which dispensed with the heavy side armor of earlier designs in favor of very high speed; this has led to them being described as "proto-battlecruisers." As a reaction to these very large ships while Brin was out of power, the navy acquired the three smaller s. The last of the second generation of ironclads, the , were again designed by Brin.

The second generation of Italian ironclads had uneventful careers, spending much of their time occupied with training exercises. Despite Italy's rivalry with the Austro-Hungarian Empire, Italy signed the Triple Alliance with Germany and Austria-Hungary in 1882, redirecting Italian naval strategy against France. Thus, the exercises of the period simulated battles with the French navy. Some of the ships saw action during the Italo-Turkish War of 1911–1912, where they provided gunfire support to Italian forces in North Africa, and those still in service by the time Italy entered World War I in 1915 continued to serve as guard ships in Italian ports in the Adriatic Sea. Most of the ships that were still extant after the war were broken up in the 1920s, though , which had been converted into a floating oil tank, was still in the inventory during World War II, and she was sunk by Allied bombers in 1943.

+ Key Armament The number and type of the primary armament Armor The maximum thickness of the belt armor (or deck armor, where applicable) Displacement Ship displacement at full combat load Propulsion Number of shafts, type of propulsion system, and top speed generated Service The dates work began and finished on the ship and its ultimate fate Laid down The date the keel assembly commenced Commissioned The date the ship was commissioned

Formidabile class

The first Italian ironclads, the two -class ships, were actually ordered from a French shipyard by the Kingdom of Sardinia in 1860, shortly before the unification of Italy under the Sardinian King Victor Emmanuel II. The two ships were initially conceived as armored floating batteries similar to the French that had proved so effective at the Battle of Kinburn in 1855. After work on the ships had begun, they were redesigned as sea-going broadside ironclads, which necessitated a reduction in their artillery battery by a third (from thirty to twenty guns). They formed the basis for an ironclad fleet aimed at defeating the Austrian Navy, since the Austrian Empire was the primary obstacle to the unification of all lands claimed by Italy.Ordovini et al., p. 328Gardiner, pp. 334–335, 337

Both ships saw action against Austrian forces during the Third Italian War of Independence in 1866, including during the Lissa campaign, though neither ship participated in the Battle of Lissa itself. had been too badly damaged during an attack on the main coastal fortifications on the island the day before the battle and had been forced to withdraw, while had been stationed to the south and her captain delayed rejoining the fleet until after the battle had ended.Greene & Massignani, pp. 217–222Wilson, pp. 219–241 Both were modernized in the 1870s, though they had become obsolete due to the rapid pace of naval developments during the period, being surpassed first by central battery ships and then by turret ships.Sondhaus (2001), p. 112 and served as training ships from the mid-1880s until they were scrapped in 1903 and 1904, respectively.

+ Summary of the class Ship ArmamentGardiner, p. 337 Armor Displacement Propulsion Service Laid down Commissioned Fate 4 × guns16 × guns One shaft, single-expansion steam engine, December 1860 May 1862 Broken up, 1903 June 1860 September 1861 Broken up, 1904

Principe di Carignano class

At the same time that Sardinia ordered the two -class ships, the navy also awarded contracts for a pair of unarmored steam frigates, and . Like the s, these two ships were redesigned after they had been laid down to convert them into broadside ironclads. A third ship, , was too far advanced in her construction to allow for conversion, and so she was completed as a wooden vessel. To replace , the navy ordered another member of the class, , which was built to a modified design. The primary difference between the first two vessels and was the lack of a complete armored belt; she had armor protection just for the bow and stern. All three ships carried a battery of twenty-two and guns, though had ten of the former and twelve of the latter, while and both had four and eighteen, respectively.Ordovini et al., p. 334Gardiner, pp. 335, 338

was the only member of the class to have been completed in time for the Third Italian War of Independence. She took part in the Battle of Lissa, though she was the lead ship in the Italian line of battle, and was not heavily engaged in the action, since the Austrian commander, Rear Admiral Wilhelm von Tegetthoff, had attacked the Italian fleet at its center.Greene & Massignani, p. 232Wilson, pp. 232–241 Like the s, the -class ships rapidly became obsolete in the 1870s, and as a result saw limited activity for the remainder of their careers. In 1875, was sold for scrap, and the other two ships were stricken from the naval register five years later to reduce the Italian naval budget; was sold for scrap, but remained extant until 1898, when she too was ultimately broken up.Sondhaus (1994), p. 50–51

+ Summary of the class Ship ArmamentGardiner, p. 338 Armor Displacement Propulsion Service Laid down Commissioned Fate 10 × 203 mm guns12 × 164 mm guns One shaft, single-expansion steam engine, January 1861 11 June 1865 Broken up, 1875 28 September 1861 February 1867 Broken up, 1880 2 March 1863 December 1871 Broken up, 1898

Re d'Italia class

After the first orders had been placed with Italian shipyards, the newly-formed Kingdom of Italy began to place orders for additional ironclads abroad, since Italian firms did not have the capacity to accept the number of contracts required by the Italian navy. The first of these foreign-built ships, the class, were ordered from the United States, from a design based heavily on the French ironclad . They were significantly more powerful than the earlier Italian ironclads, carrying a battery of thirty-six heavy guns on the broadside. The ships proved to be disappointments in service, in part due to their sterns, which were not protected and directly led to the loss of at the Battle of Lissa. They were also poorly built; the American shipyard used unseasoned timbers to construct their hulls, and was discarded relatively early in her career after they were found to have severely rotted.Ordovini et al., p. 338

served as the flagship of the Italian fleet from her commissioning until shortly before the Battle of Lissa. The Italian fleet commander, Admiral Carlo Pellion di Persano, transferred to the brand-new turret ship moments before the Austrian fleet attacked, which created widespread confusion in the Italian fleet, which was largely not aware of the change. In the ensuing melee, had her rudder shot away, and having been rendered unmaneuverable, was rammed and sunk by the Austrian flagship, . was also rammed, but she was only lightly damaged.Wilson, pp. 220–233, 236–242Greene & Massignani, pp. 232–233 saw little activity over the next decade, like the rest of the Italian ironclad fleet. In 1875, she was discarded owing to a combination of her badly rotted hull, and as a means reduce naval expenditures while the large and very expensive s were being built.

+ Summary of the class Ship Armament Armor Displacement Propulsion Service Laid down Commissioned Fate 6 × 203 mm guns30 × 164 mm guns One shaft, single-expansion steam engine, 21 November 1861 14 September 1864 Sunk, Battle of Lissa, 1866 December 1861 23 August 1864 Broken up, 1875

Regina Maria Pia class

To continue its naval expansion program, the placed orders for four more ironclads from French shipyards in 1862. The design for the new ships was prepared by French naval constructors; since they were built by three different shipyards, they varied slightly in their dimensions, but they were broadly similar in all major respects. They carried most of their battery of twenty-six guns in the traditional broadside arrangement, with the exception of three of the 164 mm guns, which were placed in forward and rearward firing bunkers as chase guns. Though not as powerful in terms of gun power as the class that preceded them, they nevertheless proved to be more effective in service, remaining in active service until the 1880s.Gardiner, pp. 335, 339Ordovini et al., p. 342

All four ships were completed in time for the Third War of Italian independence, where they formed the core of the Italian ironclad fleet. Distributed along the Italian line, they were heavily engaged in the battle; attempted to rescue before the latter was rammed and sunk, and in the confusion, she accidentally collided with . also crashed into another Italian warship, the coastal defense ship in the melee, but none of these vessels was badly damaged.Wilson, pp. 234–238, 240, 247 The four ships served with the fleet for the next two decades, including on tours in Italy's colonial empire.Ordovini et al., pp. 343–344 All four ships were modernized in the late 1880s, and were thereafter used as training ships. , , and were stricken from the naval register in 1903–1904, while lingered on as a torpedo training ship until 1910, when she too was sold for scrapping.

+ Summary of the class Ship ArmamentGardiner, p. 339 Armor Displacement Propulsion Service Laid down Commissioned Fate 8 × 203 mm guns22 × 164 mm guns. 121 mm One shaft, single-expansion steam engine, 22 July 1862 17 April 1864 Broken up, 1904 9 November 1864 Broken up, 1903 May 1864 Broken up, 1910 11 August 1862 April 1866 Broken up, 1903

Roma class