the common English spelling of Affonso, Alonso and Alfonso, which are respectively the Galician, the Leonese and the Castilian forms of Ildefonso (Ildefonsus), the name of a saint and archbishop of Toledo in the 7th century. The name has been borne by a number of Portuguese and Spanish kings, who are distinguished collectively below.
From Alphonso I. (739-757) to Alphonso V. (9991028) the personal history of the Spanish kings of this Kings of name is unknown and their very dates are disputed.