A monarchy is a form of government in which a person, the monarch, reigns as head of state for life or until abdication, usually a hereditary position acquired by some form of nominal divine right or blessing, or religious sanction. The political legitimacy and authority of the monarch may vary from restricted and largely symbolic (constitutional monarchy), to fully autocratic (absolute monarchy), and can span across executive, legislative, and judicial domains. The succession of monarchs has mostly been hereditary, often building dynasties. However, elective and self-proclaimed monarchies (in the sense of monarchical states) have also often occurred throughout history. Aristocrats, though not inherent to monarchies, often function as the pool of persons from which the monarch is chosen, and to fill the constituting institutions (e.g. diet and court), giving many monarchies oligarchic elements. Monarchs can carry various titles such as emperor, empress, king, and queen. Monarchies can form federations, personal unions and realms with vassals through personal association with the monarch, which is a common reason for monarchs carrying several titles. Monarchies were the most common form of government until the 20th century, when republics replaced many monarchies, notably at the end of World War I. As of 2024, forty-three sovereign nations in the world have a monarch, including fifteen Commonwealth realms that share King Charles III as their head of state. Other than that, there is a range of sub-national monarchical entities. Most of the modern monarchies are constitutional monarchies, retaining under a constitution unique legal and ceremonial roles for monarchs exercising limited or no political power, similar to heads of state in a parliamentary republic. Some countries have preserved the title of (say) "kingdom" while dispensing with an official serving monarch (note the example of Francoist Spain from 1947 to 1975) or while relying on a long-term regency (as in the case of Hungary in the Horthy era from 1920 to 1944). Source: Wikipedia (en)