Ferdinand m. Old High German fridu, Old Saxon frithu 'peace' + Proto-Germanic *nanþ- 'brave, daring'.
The name of an 11th C emperor of Spain and king of Castile and León, the birth name of a 12th C Italian saint, a 12th C king of León, a 13th C king of Castile and León, a 13th-14th C king of Castile and León, a 14th C king of Portugal, a 15th C king of Aragon, two 15th C kings of Naples, a 15th-16th C king of Aragon, Castile, and León, and a 16th C Holy Roman emperor and king of Germany, Hungary, Croatia, and Bohemia.
The name reached Spain via the Visigoths, and spread throughout the rest of Europe in the 16th C as a result of the Habsburgs.