FERDINAND, a name common among the royal families of some of the European states. Of the most distinguished or notorious of those who have borne this title we may mention Ferdinand I. of Austria, younger brother of Charles V., born 1503, died 1564; his grandson Ferdinand II. of Austria, who came to the throne in 1619, and died in 1637. Of the Neapolitan Ferdinands may be noticed—Ferdinand I., natural son of Alfonso V. of Aragon and Sicily, born in 1423, died in 1494; his grandson Ferdinand II., who died in 1496; Ferdinand III., who became Ferdinand V. of Spain and Ferdinand IV. of Naples, or I. of the united kingdom of the Two Sicilies, born 1751, died 1825. Of the Spanish Ferdinands the most noted was Ferdinand II. of Aragon, the husband of Isabella of Castile, born 1453, died 1516; by whose union the Spanish monarchy was consolidated.