Monarch in the context of "Archon basileus"

A declaration of war is a formal act by which one state announces existing or impending war activity against another. The declaration is a performative speech act (or the public signing of a document) by an authorized party of a national government, in order to create a state of war between two or more states.

The legality of who is competent to declare war varies between nations and forms of government. In many nations, that power is given to the head of state or sovereign. In other cases, something short of a full declaration of war, such as a letter of marque or a covert operation, may authorise war-like acts by privateers or mercenaries. The official international protocol for declaring war was defined in the Hague Convention (III) of 1907 on the Opening of Hostilities.

A polity is a group of people with a collective identity, who are organized by some form of political, institutionalized, social relations, and have a capacity to mobilize resources. It is the unit or entity of a political community or body politic.

A polity can be any group of people organized for governance, such as by the board of a corporation, and in the case of a federal country, the government that exists at both its federal level and the level of its subdivided regions. A polity may have various forms, such as a republic administered by an elected representative, a realm of a hereditary monarch, an incorporated city managed by an appointed mayor, and many others.

Basileus (Ancient Greek: βασιλεύς) is a Greek term and title that has signified various types of monarchs throughout history. In the English-speaking world, it is perhaps most widely understood to mean 'monarch', referring to either a 'king' or an 'emperor'. The title was used by sovereigns and other persons of authority in ancient Greece (especially during the Hellenistic period), the Byzantine emperors, and the kings of modern Greece. The name Basileios (Basil), deriving from the term basileus, is a common given name in the Eastern Orthodox Church and Syriac Orthodox Church for the Maphrian.

The feminine forms are basileia (βασίλεια), basilissa (βασίλισσα), basillis (βασιλίς), or the archaic basilinna (βασιλίννα), meaning 'queen' or 'empress'. The related term basileia (βασιλεία) has meanings such as 'sovereignty', 'royalty', 'kingdom', 'reign', 'dominion' and 'authority'.

A personal union is a combination of two or more monarchical states that have the same monarch while their boundaries, laws, and interests remain distinct. A real union, by contrast, involves the constituent states being to some extent interlinked, such as by sharing some limited governmental institutions. It differs from a federation in that each constituent state has an independent government, whereas a federal state is united by a central government. The ruler in a personal union does not need to be a hereditary monarch.

The term was coined by German jurist Johann Stephan Pütter, introducing it into Elementa iuris publici germanici (Elements of German Public Law) of 1760.

An oath of allegiance is an oath whereby a subject or citizen acknowledges a duty of allegiance and swears loyalty to a monarch or a country. In modern republics, oaths are sworn to the country in general, or to the country's constitution. For example, officials in the United States, take an oath of office that includes swearing allegiance to the United States Constitution. However, typically in a constitutional monarchy, such as in the United Kingdom, Australia, and other Commonwealth realms, oaths are sworn to the monarch. Armed forces typically require a military oath.

In feudal times, a person would also swear allegiance to their feudal superiors. To this day the oath sworn by freemen of the City of London contains an oath of obedience to the Lord Mayor of the City of London.

The term "high priest" usually refers either to an individual who holds the office of ruler-priest, or to one who is the head of a religious organisation.

Archon (Greek: ἄρχων, romanized: árchōn, plural: ἄρχοντες, árchontes) is a Greek word that means "ruler", frequently used as the title of a specific public office. It is the masculine present participle of the verb stem αρχ-, meaning "to be first, to rule" (see also ἀρχή "beginning, origin"), derived from the same root as words such as monarch and hierarchy.

The aristocracy (from Greek ἀριστοκρατία aristokratía, "rule of the best"; Latin: aristocratia) is historically associated with a "hereditary" or a "ruling" social class. In many states, the aristocracy included the upper class with hereditary rank and titles. They are usually below only the monarch of a country or nation in its social hierarchy.