FERDINAND IV. (III. of Sicily, and I. of the Two Sicilies) (1751-1825), king of Naples, third son of Don Carlos of Bourbon (afterwards Charles III. of Spain), king of Naples and Sicily, was born in Naples on Jan. 12, 5 1. When his father ascended the Spanish throne in Ferdinand, in accordance with the treaties forbidding the union of the two crowns, succeeded him as king of Naples, under a regency presided over by the Tuscan Bernardo Tanucci, who neglected the young king's education, and left him to indulge in his liking for low life. Ferdinand's minority ended in 1767, and his first act was the expulsion of the Jesuits. In 1768 he married Maria Carolina, daughter of the empress Maria Theresa. The queen secured the dismissal of Tanucci, and with the help of Sir John Acton (q.v.), who eventually became prime minister, sought independence of the Spanish connection and a rapprochement with England and Austria. From the day of the execution of her sister Marie Antoinette, the queen lived in terror of revolution and Naples joined the coalition against France in 1793. For the history of Ferdinand's intervention in the revolutionary war, the establish ment of the Parthenopean republic at Naples, and the savage reaction after the recapture of Naples by the army of brigands and gaol-birds under Cardinal Ruffo, see NAPLES : History. Ferdi nand had to flee to Sicily in 1806, where he reigned under British protection while Joseph Bonaparte ruled in Naples. Lord Bentinck, the British resident in Sicily, procured the queen's exile to Austria, and Ferdinand allowed his son Francis (after wards Francis I. of the Two Sicilies) to act as regent in Sicily.
He returned to Naples after the fall of Napoleon, and pro claimed the kingdom of the Two Sicilies. He was now completely subservient to Italy. Ruthless repression of all Liberal opinion favoured the spread of the secret society of the Carbonari (q.v.). After the revolt of Gen. Pepe (182o) Ferdinand granted a paper constitution, thus securing the help of his Neapolitan subjects in quelling an insurrection in Sicily. The success of the military revolution in Naples alarmed the Powers of the Holy Alliance. Ferdinand was invited to the congress of Laibach (q.v.) to ex plain the situation. His cynical repudiation at Laibach of the constitution he had granted made conciliation in Naples hopeless. An Austrian army occupied Naples, and Pepe was defeated. The parliament was now dismissed, and Ferdinand inaugurated an era of savage persecution, supported by spies and informers, against the Liberals and Carbonari, the Austrian commandant in vain protesting against the savagery which his presence alone rendered possible.
Ferdinand died on Jan. 4, 18 2 5. Few sovereigns have left be hind so odious a memory. His whole career is one long of perjury, vengeance and meanness, unredeemed by a single generous act, and his wife was a worthy helpmeet and actively co-operated in his tyranny.