Until 1980, no monarchy let an eldest daughter outrank her younger brothers
For most of history crowns passed to sons first. Sweden broke that rule in 1980, becoming the first monarchy to hand the throne to the eldest child regardless of sex, and a string of European kingdoms followed. Britain joined only in 2013, after sixteen Commonwealth realms agreed together.
A monarch is head of state for life or until abdicating, usually inheriting the throne but sometimes chosen from an eligible family or simply seizing it, as many ancient Greek tyrants did. Titles vary enormously: king, emperor, grand duke, emir, sultan, pharaoh. When a small child inherits, a regent governs until adulthood. Pharaohs alone ruled Egypt for some three millennia, from about 3150 BC until the Roman conquest in 31 BC.
Succession rules have been endlessly inventive. Salic law, used in France and the Savoy lands in Italy, barred women entirely; many realms instead let daughters inherit before distant male cousins, sometimes making the heiress's husband king. Germanic states of the Holy Roman Empire often split lands among sons, while Celtic tanistry was partly elective and weighed ability. As lifespans lengthened, eldest sons more often came of age before their fathers died, so primogeniture gradually won out over its rivals. Saudi Arabia still usually passes the crown along a line of brothers, and Jordan's king picks his own successor.
Election has a long pedigree too. Prince-electors chose Holy Roman Emperors, though usually from one dynasty, and the Polish–Lithuanian Commonwealth held free royal elections. Malaysia's Conference of Rulers appoints a king every five years, and cardinals elect the pope, sovereign of Vatican City, for life. Supporters of hereditary rule point to seamless continuity, captured in the cry that the king is dead and long live the king, while in constitutional monarchies real power lies elsewhere.
The Americas had their own kings before Europeans arrived, and after colonisation new crowns appeared. Jean-Jacques Dessalines declared himself Emperor of Haiti on September 22, 1804, and Brazil was ruled by emperors from 1822 to 1889 under Pedro I and Pedro II. Across all systems, usurpers have repeatedly toppled rulers and installed their own families.
Source: Monarch
