From the Wikipedia page:
A monarchy is a form of government in which a person, the monarch, is head of state for life or until abdication. The political legitimacy and authority of the monarch may vary from restricted and largely symbolic (constitutional monarchy), to fully autocratic (absolute monarchy), and can expand across the domains of the executive, legislative, and judicial.
The word "monarch" (Late Latin: monarchia) comes from the Ancient Greek word μονάρχης (monárkhēs), derived from μόνος (mónos, "one, single") and ἄρχω (árkhō, "to rule"): compare ἄρχων (árkhōn, "ruler, chief"). It referred to a single at least nominally absolute ruler. In current usage the word monarchy usually refers to a traditional system of hereditary rule, as elective monarchies are quite rare.
The similar form of societal hierarchy known as chiefdom or tribal kingship is prehistoric. Chiefdoms provided the concept of state formation, which started with civilizations such as Mesopotamia, Ancient Egypt and the Indus Valley civilization. In some parts of the world, chiefdoms became monarchies. Some of the oldest recorded and evidenced monarchies were Narmer, Pharaoh of Ancient Egypt c. 3100 BCE, and Enmebaragesi, a Sumerian King of Kish c. 2600 BCE.
From earliest records, monarchs could be directly hereditary, while others were elected from among eligible members. With the Egyptian, Indian, Mesopotamian, Sudanic, reconstructed Proto-Indo-European religion, and others, the monarch held sacral functions directly connected to sacrifice and was sometimes identified with having divine ancestry, possibly establishing a notion of the divine right of kings.
Monarchies run the gamut: from absolute and constitutional, to tetrarchies and triarchies. In all, there are twenty-one different types of monarchies that have existed in the world at one time or another. In the micronational world, there have been at least a fifth of that numer have been employed for monarchial use. Kings, queens, princes and princesses, dukes and duchess of various types nd ranks have come and gone. Some continue to exist to this day.
For the majority of micronational monarchies, the philosophy of being of service to the people remains a strong undercurrent. It is even indicative in the rule of the patron saint of micronationality, Emperor Norton I of the Empire of the United States. The existence and efforts of monarchies in the micronational world often work towards bettering the overal image of monarchy in the eyes of the world: an image that has been tainted over centuries by so many macronationl counterparts that have come before. The efforts, as some micronational monarchs might put it, are a work in progress.
But then, building a better view of the world and how it can be from a monarchial view - or any worthwhile view, for that matter - is always a work in progress.