Original: When Ferdinand succeeded his father as King of Aragon in 1479 , the Crown of Castile and the various territories of the Crown of Aragon were united in a personal union creating for the first time since the 8th century a single political unit referred to as España ( Spain ) , the root of which is the ancient name Hispania .
Simplified: For the first time since the 8th century this created a single political unit which might be called Spain , although the various territories were not properly administered as a single unit until the 18th century .