Eurico Cialdlyi, an Italian soldier, born near Castelvetro, Aug. 8, 1811. He is the son of a hydrographical engineer and a Spanish lady. Expelled from the Jesuit college at Reggio on account of his irreverence, though displaying precocious talents, he was sent to Parma to study medicine and the art of design, but joined the revolutionary movement of 1831, and was obliged to take refuge in Paris, where he continued his medical studies, and supported himself by translating into Italian some writings of Voltaire and Rousseau, and some of Velpeau's surgical works. In 1833 he fought in Portugal for Dom Pedro, and in 1835 he entered the Spanish service against Don Carlos, rising to the rank of lieutenant colonel. After the war he served for some time as adjutant of Narvaez at Valencia, where he married a Spanish lady. He was sent to Paris to report upon the organization of the French police, and after the outbreak of the revolution of 1848 joined Gen. Durando at Vicenza. Being severely wounded (June 10), he fell into the hands of the Austrians, but was set free early in 1849, after his partial recovery. He afterward fought against the Austrians as commander of a corps chiefly made up of volunteers.

In the Crimean war he became brigadier general, Aug. 1, 1855; and on his return to Turin the king appointed him his aide-de-camp, though that rank is generally conferred only on noblemen. In 1859 he organized the Garibaldian corps of Alpine sharpshooters, and commanded the 4th division of the army, attaining the rank of general of division (June 1) in reward for his services especially at the battle of Palestro. In 1800 he commanded in the brilliant campaign which resulted in the utter defeat of the papal army under Lamoriciere at Castelfidardo (Sept. 18), and in the capture of Ancona and other important places, after which he was made general of the army (a rank corresponding to that of marshal in France), simultaneously with Garibaldi and Fanti. On Feb. 13,1861, he compelled the surrender of Gaeta, and on March 13 that of the citadel of Messina, thus closing the war in southern Italy and Sicily. He declined the titles and pensions offered to him, accepting only a crown of laurel in token of national gratitude. He was elected member of parliament for Reggio, but went in 1861 as lieutenant of the king to Naples, where he did much to extirpate pseudo-political brigandage.

When Garibaldi began his revolutionary movement of 1862, Cialdini was sent to Sicily to preserve order in that island; but the defeat of the former at Aspromonte put an end to this mission, and he resumed the military command of Bologna. In 1864 he became a member of the senate, and urged the removal of the capital to Florence as a strategical necessity. In February, 1865, the king appointed him military commander at Turin. In 1866, as commander of the 4th corps, he operated along the lower banks of the Po, with a view of cutting the Austrian communications east of the quadrilateral. After the disastrous battle of Custozza he was obliged to fall back upon Bologna and Piacenza; but after the battle of Sadowa he was of some service in hastening the retreat of the Austrians toward Tyrol. He succeeded La Marmora as chief of staff, and declined in October, 1867, the mission to Vienna. When Rattazzi's cabinet was broken up on account of the differences with France, the king requested Cialdini to form a new cabinet; but his efforts were unavailing, and in November he became commander-in-chief of the troops in central Italy. In 1869 he had bitter controversies with La Marmora in respect to the disastrous campaign of 1866, and he soon retired from the army in order to bo entirely independent as one of the leaders of the opposition in the senate against Lanza's administration.

He was one of the signers of the act by virtue of which the throne of Spain was accepted by Amadeus, whom he accompanied as extraordinary ambassador to Spain, but without any official title. In February, 1873, he was sent on a special diplomatic mission to France.