Rule by a king or a queen, usually of one family or dynasty or aristocratic clan or House that manages to acquire an empire. Pure Monarchy, although common in medieval and iron age Earth, has been rare since the beginning of the Industrial Age. In the present age, however, there are however numerous petty egomaniacs and eccentrics throughout the galaxy who have set up their own principalities, kingdoms and so on as minor polities. Usually these encompass, at the very most, a single hab or world and do not last for more than a few hundred years. The big so-called Monarchies are actually Theocracies or AIcracies, depending on one's point of view. The ruling AI empowers the local sovereign, who thus becomes, in the archaic phrase, "the representative of God on Earth".