Monarchy, where the divine right of kings establishes the political legitimacy of the rule of the monarch (king or queen); legitimacy also derives from the popular perception (tradition and custom) and acceptance of the monarch as the rightful ruler of nation and country. Contemporarily, such divine-right legitimacy is manifest in the absolute monarchy of the House of Saud (est. 1744), a royal family who have ruled and governed Saudi Arabia since the 18th century. Moreover, constitutional monarchy is a variant form of monarchic political legitimacy which combines traditional authority and legal–rational authority, by which means the monarch maintains nationalist unity (one people) and democratic administration (a political constitution)

In political science, legitimacy is the right and acceptance of an authority, usually a governing law or a regime. Whereas authority denotes a specific position in an established government, the term legitimacy denotes a system of government—wherein government denotes "sphere of influence"