Tribal kingship and Chiefdoms have been the most widespread form of social organisation from the Neolithic, and the predominance of monarchies has declined only with the rise of Republicanism in the modern era.
A monarchical form of government can be combined with many different kinds of political and economic systems, from absolute monarchy to constitutional monarchy and from a market economy to a planned economy.
A constitutional monarchy is a form of monarchical government established under a constitutional system which acknowledges an elected or hereditary monarch as head of state.
An absolute monarchy is a monarchical form of government where the ruler has the power to rule his or her land or country and its citizens freely, with no laws or legally-organized direct opposition in force.
A monarch may reign over multiple kingdoms, dominions or realms in various forms of political, dynastic, personal union or association.