The often overlooked title of 'prince' ("príncipe/princesa") has historically been borne by those who have been granted or have inherited that title. It is often not included in lists of the Spanish nobility because it is rare. Prince/Princess are English translations of Infante/Infanta, referring to the son or daughter of a king; such titles are reserved for members of the royal family (the heir to the throne or the consort of the Queen regnant). Historically, infante or infanta could refer to offspring, siblings, uncles and aunts of a king. The heir's princely titles derive from the ancient kingdoms which united to form Spain.