A famous bearer was the 14th-century Jewish philosopher Abner of Burgos, called Alfonso of Valladolid after he converted to Christianity. It has been used as an English Christian given name since the Protestant Reformation. It was popular with the Puritans, who brought it to America in the 17th century.
This name has never been overly common in the Christian world, and it is considered typically Jewish. It was however borne by an 11th-century Hungarian king.