Heir to the throne

An heir apparent or heiress apparent is a person who is first in line of succession and cannot be displaced from inheriting by the birth of another person. An heir presumptive, by contrast, is someone who is first in line to inherit a title but who can be displaced by the birth of a more eligible heir.

Today these terms most commonly describe heirs to hereditary titles, particularly in monarchies. They are also used metaphorically to indicate an "anointed" successor to any position of power, e.g., a political or corporate leader. Most monarchies refer to the heir apparent of their thrones with the descriptive term of crown prince but these heirs may also be also accorded with a more specific substantive title, such as Prince of Orange in the Netherlands, Prince of Asturias in Spain, or Prince of Wales in the Commonwealth realms. In France the title was le Dauphin, in Imperial Russia it was Tsesarevich.

This article primarily describes the term heir apparent in a hereditary system regulated by laws of primogeniture—as opposed to cases where a monarch has a say in naming the heir.

In a hereditary system governed by some form of primogeniture, an heir apparent is easily identifiable as the person whose position as first in the line of succession is secure, regardless of future births. An heir presumptive, by contrast, can always be "bumped down" in the succession by the birth of somebody more closely related in a legal sense (according to that form of primogeniture) to the current title-holder.

The clearest example occurs in the case of a title-holder with no children. If at any time he or she were to produce children, they (the offspring of the title-holder) rank ahead of whatever more "distant" relative (the title-holder's sibling, perhaps, or a nephew or cousin) had been heir presumptive.

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