Ahereditary monarchy is a form ofgovernment andsuccession of power in which thethrone passes from one member of aruling family to another member of the same family. A series of rulers from the same family would constitute adynasty. It is historically the most common type ofmonarchy and remains the dominant form in extant monarchies.
In most extanthereditary monarchies, the typical order of succession uses some form ofprimogeniture, but there exist other methods such asseniority andtanistry (in which an heir-apparent is nominated from among qualified candidates). Research shows that hereditary regimes, in particularprimogeniture, are more stable than forms of authoritarian rule with alternative succession arrangements.[1][2][3][4][5][6]

Theoretically, when the monarch of a hereditary monarchy dies or abdicates, the crown typically passes to the next generation of the family. If no qualified child exists, the crown may pass to a brother, sister, nephew, niece, cousin, or other relative, in accordance with a predefinedorder of succession, often enshrined in legislation. Such a process establishes who will be the next monarch beforehand and avoids disputes among members of the royal family.Usurpers may resort to inventing semi-mythical genealogies to bolster their respectability.[8]
Historically, there have been differences in systems ofsuccession, mainly revolving around the question of whether succession is limited to males or whether females are also eligible (historically, the crown often devolved on the eldest surviving female child, as the ability to lead an army in battle was a requisite of kingship[citation needed]).Agnatic succession refers to systems where females are neither allowed to succeed nor to transmit succession rights to their male descendants (as according to theSalic law).[9] Anagnate is akinsman with whom one has a common ancestor by descent in an unbroken male line.Cognatic primogeniture allows both male and female descendants to succeed, butmales are usually given preference however gender equality has been an advocacy of the state in recent years. Inabsolute primogeniture, the eldest child can succeed to the throne regardless of sex; this system wasadopted in 2011 by themonarchies in the Commonwealth (though not retrospectively affecting the order of succession).[10] Another factor which may be taken into account is the religious affiliation of the candidate or the candidate'sspouse, specifically where the monarch also has a religious title or role; for example, the British monarch has the title ofsupreme governor of the Church of England and may not professRoman Catholicism.[11]
To legitimise the rise to power of new tribal or dynastic groups Gaelic genealogists often forged a link between the usurper and thedynasty they had overthrown.