Head of state in the context of "Stadtholder"

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.

The Government of Japan is the central government of Japan. It consists of legislative, executive and judiciary branches and functions under the framework established by the Constitution of Japan. Japan is a unitary state, containing forty-seven administrative divisions, with the emperor as its head of state. His role is ceremonial and he has no powers related to the Government. Instead, it is the Cabinet, comprising the prime minister and the ministers of state, that directs and controls the government and the civil service. The Cabinet has the executive power and is formed by the prime minister, who is the head of government. The Prime Minister is nominated by the National Diet and appointed to office by the Emperor. The current cabinet is the Takaichi Cabinet, which is led by prime minister Sanae Takaichi, who assumed office on 21 October 2025. The country has had a Liberal Democratic minority government since 2025.

The National Diet is the legislature, the organ of the Legislative branch. The Diet is bicameral, consisting of two houses with the House of Councilors being the upper house, and the House of Representatives being the lower house. The members of both houses of the Diet are directly elected by the people, who are the source of sovereignty. The Diet is defined as the supreme organ of sovereignty in the Constitution. The Supreme Court and other lower courts make up the Judicial branch and have all the judicial powers in the state. The Supreme Court has ultimate judicial authority to interpret the constitution and the power of judicial review. The judicial branch is independent from the executive and the legislative branches. Judges are nominated or appointed by the Cabinet and never removed by the executive or the legislature except during impeachment.

The emperor of Japan is the hereditary monarch and head of state of Japan. The emperor is defined by the Constitution of Japan as the symbol of the Japanese state and the unity of the Japanese people, his position deriving from "the will of the people with whom resides sovereign power". The Imperial Household Law governs the line of imperial succession. Pursuant to his constitutional role as a national symbol, and in accordance with rulings by the Supreme Court of Japan, the emperor is personally immune from prosecution. By virtue of his position as the head of the Imperial House, the emperor is also recognized as the head of the Shinto religion, which holds him to be the direct descendant of the sun goddess Amaterasu. According to tradition, the office of emperor was created in the 7th century BC, but the first historically verifiable emperors appear around the 5th or 6th centuries AD.

The role of the emperor of Japan has historically alternated between a largely ceremonial symbolic role and that of an actual imperial ruler. Since the establishment of the first shogunate in 1192, the emperors of Japan have rarely taken on a role as supreme battlefield commander, unlike many Western monarchs. Japanese emperors have nearly always been controlled by external political forces, to varying degrees. Between 1192 and 1867, the shōguns, or their shikken regents in Kamakura (1203–1333), were the de facto rulers of Japan, although they were nominally appointed by the emperor. After the Meiji Restoration in 1868, the emperor was the embodiment of all sovereign power in the realm, as enshrined in the Meiji Constitution of 1889. Since the enactment of the 1947 constitution, the role of emperor has been relegated to that of a ceremonial head of state without even nominal political powers. The emperor is the head of the Japanese honors system, conferring orders, decorations, medals, and awards in the name of the state and on behalf of its people in accordance with the advice of the Cabinet.

An official residence is a residence designated by an authority and assigned to an official (such as a head of state, head of government, governor, or other senior figures), and may be the same place where the office holder conducts their work functions or lives.

Monaco, officially the Principality of Monaco, is a sovereign city-state and microstate in Western Europe. Situated on the French Riviera, it is a semi-enclave bordered by France to the north, east, and west, with the Mediterranean Sea to the south; the Italian region of Liguria is about 15 km (9.3 mi) east. With a population of 38,423 living in an area of 2.08 km (0.80 sq mi), Monaco is the second smallest sovereign state in the world, after Vatican City, as well as the most densely populated. It also has the world's shortest national coastline of any non-landlocked nation, at 3.83 km (2.38 mi). Fewer than 10,000 of its residents are Monégasque nationals. While the official language of Monaco is French, Italian and Monégasque are also widely spoken and understood.

Monaco is governed under a form of semi-constitutional monarchy, with Prince Albert II as head of state, who holds substantial political powers. The prime minister, who is the head of government, can be either a Monégasque or French citizen; the monarch consults with the Government of France before an appointment. Key members of the judiciary are detached French magistrates. The House of Grimaldi has ruled Monaco, with brief interruptions, since 1297. The state's sovereignty was officially recognised by the Franco-Monégasque Treaty of 1861, with Monaco becoming a full United Nations voting member in 1993. Despite Monaco's independence and separate foreign policy, its defence is the responsibility of France, notwithstanding two small military units.

A commander-in-chief or supreme commander (supreme commander-in-chief) is the person who exercises supreme command and control over an armed force or a military branch. As a technical term, it refers to military competencies that reside in a country's executive leadership, a head of state, head of government, or other designated government official.

While often used interchangeably, the title of Supreme Commander–in–Chief is technically different, since the two titles can be in use simultaneously. For example, in the case of the Armed Forces of Ukraine, the supreme commander-in-chief is the president of Ukraine, while the commander-in-chief is its professional head.

The pope is the bishop of Rome and the head of the worldwide Catholic Church. He is also known as the supreme pontiff, Roman pontiff, or sovereign pontiff. From the 8th century until 1870, the pope was the sovereign or head of state of the Papal States, and since 1929 of the much smaller Vatican City State. From a Catholic viewpoint, the primacy of the bishop of Rome is largely derived from his role as the apostolic successor to Saint Peter, to whom primacy was conferred by Jesus, who gave Peter the Keys of Heaven and the powers of "binding and loosing", naming him as the "rock" upon which the Church would be built. The current pope is Leo XIV, who was elected on 8 May 2025 on the second day of the 2025 papal conclave.

While his office is called the papacy, the jurisdiction of the episcopal see is called the Holy See. The word see comes from the Latin for 'seat' or 'chair' (sede, referring in particular to the one on which the newly elected pope sits during the enthronement ceremony). The Holy See is a sovereign entity under international law; it is headquartered in the distinctively independent Vatican City, a city-state which forms a geographical enclave within the conurbation of Rome. It was established by the Lateran Treaty in 1929 between Fascist Italy and the Holy See to ensure its political and spiritual independence. The Holy See is recognized by its adherence at various levels to international organizations and by means of its diplomatic relations and political accords with many independent states.

The British Overseas Territories (BOTs) are fourteen territories that maintain a constitutional or historically recognised connection with the United Kingdom (UK) and constitute part of its sovereign territory, yet lie outside the British Islands. These territories are remnants of the former British Empire which remained under British sovereignty following decolonisation, albeit with varying constitutional statuses.

The permanently inhabited territories exercise varying degrees of internal self-governance, although the UK retains ultimate constitutional oversight, and authority over defence, foreign relations and internal security. While three of the territories are inhabited primarily by military or scientific personnel, the remainder host substantial civilian populations. All fourteen territories recognise the British monarch as head of state and oversight is primarily exercised by the Foreign, Commonwealth and Development Office (FCDO). The total land area of all the BOTs make up 18,015 km (6,956 sq mi), roughly the size of Fiji, which was itself a former British colony.

The European Council (informally EUCO) is a collegiate body (directorial system) and a symbolic collective head of state, that defines the overall political direction and general priorities of the European Union (EU). It is composed of the heads of state or of government of the EU member states, the president of the European Council, and the president of the European Commission. The High Representative of the Union for Foreign Affairs and Security Policy also takes part in its meetings.

Established as an informal summit in 1975, the European Council was formalised as an institution in 2009 upon the commencement of the Treaty of Lisbon. Its current president is António Costa, former prime minister of Portugal.

A palace is a large residence, often serving as a royal residence or the home for a head of state or another high-ranking dignitary, such as a bishop or archbishop. The word is derived from the Latin name palātium, for Palatine Hill in Rome which housed the Imperial residences.

Most European languages have a version of the term (palats, palais, palazzo, palacio, etc.) and many use it to describe a broader range of buildings than English. In many parts of Europe, the equivalent term is also applied to large private houses in cities, especially of the aristocracy. It is also used for some large official buildings that have never had a residential function; for example in French-speaking countries Palais de Justice is the usual name of important courthouses. Many historic palaces such as parliaments, museums, hotels, or office buildings are now put to other uses. The word is also sometimes used to describe an elaborate building used for public entertainment or exhibitions such as a movie palace.