A monarchy is a governmental system in which the head of state is a single person. Typically, the position is hereditary, as is the case with famous monarchies like that of the United Kingdom. Originally, the term was used to refer to a system of government in which the monarch had absolute authority, but the term has evolved to encompass any country with a hereditary head of state, regardless as to how much power is vested in the head of state.

The monarchy is probably the oldest system of government, since it would have evolved naturally from tribal governments ruled through dynastic alliances. At one point, most of the governments in the world were monarchies. In the modern world, over 40 countries are monarchies, which is a fact that some people are surprised to learn.

The classic form of a monarchy is an absolute monarchy. In this type of monarchy, the monarch has total authority over the government and his or her people. A cabinet of advisers may be assembled to assist the monarch, but they cannot make major decisions. This type of monarchy is increasingly rare, since most nations value more freedoms for their people. Levels of happiness under an absolute monarchy vary widely, and such governments are usually closely scrutinized by neighboring nations.

In a constitutional monarchy, the monarch shares power with a house of representatives or congress. The monarch may make important government decisions and actively participate in the running of the nation, but he or she does not do so alone. Much like a president in a constitutional democracy, the monarch is usually able to veto legislation which he or she feels is contrary to the interest of the country. The monarch may also be able to dissolve Parliament, usually at the specific request of the Prime Minister.

In many cases, the system of a monarchy has been retained because it is an important aspect of the cultural and political history of the nation. The monarch is a living representative of generations of rulers, and is treated as a figure of reverence. Some well known constitutional monarchies include the United Kingdom, Belgium, Cambodia, Spain, and Thailand. Famous absolute monarchies include the Sultanates of Brunei and Oman, the Kingdom of Bhutan, and Saudi Arabia. The Vatican is also technically a monarchy, ruled by the Supreme Pontiff, the Pope. Unlike most monarchies, however, this position is not hereditary.