In most countries with monarchies, the monarch serves as a symbol of continuity and statehood. Many states have a strong convention against the monarch becoming involved in partisan politics. In some cases, the symbolism of monarchy alongside the symbolism of a republic cause the combination to be divisive. For example, there is the case of Australia where the question of retaining a monarch as head of state touches on divisive and controversial questions of national identity.
Monarchies are one of the oldest forms of government, with echoes in the leadership of tribal chiefs. Most monarchies begin as absolute monarchies, in a society with technologies that allow the concentration and organization of power but not enough for education and rapid communication to flourish. The economic structure of such monarchies is that of concentrated wealth, with the majority of the population as agricultural serfs.
Since 1800, many of the world's monarchies have become republics. Most countries which retain monarchy have limited the monarch's power, with most having become constitutional monarchies. England's monarchy was famously limited by the Magna Carta of 1215. Swaziland is the only country that retains an absolute monarchy, although the Middle Eastern monarchies certainly lean further in that direction than those in Europe; however we should also note recent (2003) developments in Liechtenstein.
In some cases, a hereditary monarchy exists, but actual power resides in the military. This has often historically been the case in Thailand and Japan. In Fascist Italy a monarchy coexisted with a fascist party for longer than such coexistences occurred in Rumania, Hungary, Greece and Yugoslavia, but for a shorter period than such coexistence occurred in Spain.
On several occasions throughout history, the same person has served as monarch of separate independent states, such as Australia, Canada, New Zealand, the United Kingdom and several other countries today. In some cases, such as England and Scotland a personal union was the precursor to a merger of the states.
The rules for selection of monarchs varies from country to country. In constitutional monarchies the rule of succession is generally embodied in a law passed by parliament. Most European monarchical states of the 21st century practise primogeniture: the royal line passes through the eldest surviving male and then the eldest female if no males survive. In Japan, the current succession law does not permit females to ascend the throne although this has occurred in the past and there have been suggestions to change this. In earlier times, the succession was often unclear and this lead to a number of wars.
Monarchies can come to an end in several ways. There may be a revolution in which the monarchy is overthrown; or, as in Italy, there may be a referendum in which the electorate decides to form a republic. In some cases, as with England and Spain, the monarchy may be overthrown and then restored.
Sometimes, component members of federal states are monarchies, even though the federal state as a whole is not; for example each of the emirates that form the United Arab Emirates has its own monarch (an emir).
Another unique situation is Malaysia, in which the national king is elected for a five year term from and by the nine sultans who are the hereditary rulers of the states of the Malay peninsula.
Note that monarchy (literally rule by a single person, from the Greek) also has echoes of autocratic executives in commercial enterprises, especially private or family-controlled companies.
Monarchical states today (2002) include :