Hereditary succession within one
patrilineal family has been most common (but see the
Rain Queen), with a preference for children over siblings, and sons over daughters. In Europe, some people practiced equal division of land and regalian rights among sons or brothers, as in the Germanic states of the Holy Roman Empire, until after the
medieval era and sometimes (e.g.,
Ernestine duchies) into the 19th century. Other European realms practiced one or another form of
primogeniture, in which a
lord was succeeded by his eldest son or, if he had none, by his brother, his daughters or sons of daughters. The system of
tanistry practiced among Celtic tribes was semi-elective and gave weight also to ability and merit. The
Salic law, practiced in France and in the Italian territories of the
House of Savoy, stipulated that only men could inherit the crown. In most
fiefs, in the event of the demise of all legitimate male members of the
patrilineage, a female of the family could succeed (semi-Salic law). In most realms, daughters and sisters were eligible to succeed a ruling kinsman before more distant male relatives (male-preference primogeniture), but sometimes the husband of the heiress became the ruler, and most often also received the title,
jure uxoris. Spain today continues this model of succession law, in the form of
cognatic primogeniture. In more complex medieval cases, the sometimes conflicting principles of
proximity and
primogeniture battled, and outcomes were often idiosyncratic. As the average life span increased, the eldest son was more likely to reach majority age before the death of his father, and primogeniture became increasingly favored over proximity, tanistry, seniority, and election. In 1980,
Sweden became the first monarchy to declare
equal primogeniture,
absolute primogeniture or
full cognatic primogeniture, meaning that the eldest child of the monarch, whether female or male, ascends to the throne. Other nations have since adopted this practice:
Netherlands in 1983,
Norway in 1990,
Belgium in 1991,
Denmark in 2009, and
Luxembourg in 2011. The
United Kingdom adopted absolute (equal) primogeniture on April 25, 2013, following
agreement by the prime ministers of the sixteen Commonwealth Realms at the 22nd Commonwealth Heads of Government Meeting. In some monarchies, such as
Saudi Arabia, succession to the throne usually first passes to the monarch's next eldest brother and so on through his other brothers, and only after them to the monarch's children (
agnatic seniority). In some other monarchies (e.g.,
Jordan), the monarch chooses who will be his successor within the royal family, who need not necessarily be his eldest son. Lastly, some monarchies are
elective (
UAE,
Malaysia,
Holy See and
Cambodia), meaning that the monarch is elected instead of assuming office due to direct inheritance. Rules and laws regarding election vary country to country. Whatever the rules of succession, there have been many cases of a monarch being overthrown and replaced by a usurper who would often install his own family on the throne. ==Examples of monarchs==