War in the context of "Internecine war"

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.

Borders are generally defined as geographical boundaries, imposed either by features such as oceans and terrain, or by political entities such as governments, sovereign states, federated states, and other subnational entities. Political borders can be established through warfare, colonization, or mutual agreements between the political entities that reside in those areas.

Some borders—such as most states' internal administrative borders, or inter-state borders within the Schengen Area—are open and completely unguarded. Most external political borders are partially or fully controlled, and may be crossed legally only at designated border checkpoints; adjacent border zones may also be controlled. For the purposes of border control, airports and seaports are also classed as borders. Most countries have some form of border control to regulate or limit the movement of people, animals, and goods into and out of the country. Under international law, each country is generally permitted to legislate the conditions that have to be met in order to cross its borders, and to prevent people from crossing its borders in violation of those laws.

Conquest involves the annexation or control of another entity's territory through war or coercion. Historically, conquests occurred frequently in the international system, and there were limited normative or legal prohibitions against conquest.

The onset and diffusion of nationalism (the belief that nation and state should be congruent), especially in the 19th century, made the idea of conquest increasingly unacceptable to popular opinion. Prohibitions against conquest were codified with the establishment of the League of Nations following World War I and of the United Nations at the end of World War II.

Repatriation is the return of the cultural property, often referring to ancient or looted art, to their country of origin or former owners (or their heirs).

The disputed cultural property items are physical artifacts of a group or society taken by another group, usually in the act of looting, whether in the context of imperialism, colonialism, or war. The contested objects vary widely and include sculptures, paintings, monuments, objects such as tools or weapons for purposes of anthropological study, and human remains.

Ancient warfare is war that was conducted from the beginning of recorded history to the end of the ancient period. The difference between prehistoric and ancient warfare is more organization oriented than technology oriented. The development of first city-states, and then empires, allowed warfare to change dramatically. Beginning in Mesopotamia, states produced sufficient agricultural surplus. This allowed full-time ruling elites and military commanders to emerge. While the bulk of military forces were still farmers, the society could portion off each year. Thus, organized armies developed for the first time. These new armies were able to help states grow in size and become increasingly centralized.

In Europe and the Near East, the end of antiquity is often equated with the Fall of Rome in 476 AD, the wars of the Eastern Roman Empire on its Southwestern Asian and North African borders, and the beginnings of the Muslim conquests in the 7th century. In China, it can also be seen as ending of the growing role of mounted warriors needed to counter the ever-growing threat from the north in the 5th century and the beginning of the Tang dynasty in 618 AD. In India, the ancient period ends with the decline of the Gupta Empire (6th century) and the beginning of the Muslim conquests there from the 8th century. In Japan, the ancient period is considered to end with the rise of feudalism in the Kamakura period in the 12–13th century.

International law, also known as public international law and the law of nations, is the set of rules, norms, legal customs and standards that states and other actors feel an obligation to, and generally do, obey in their mutual relations. In international relations, actors are simply the individuals and collective entities, such as states, international organizations, and non-state groups, which can make behavioral choices, whether lawful or unlawful. Rules are formal, typically written expectations that outline required behavior, while norms are informal, often unwritten guidelines about appropriate behavior that are shaped by custom and social practice. It establishes norms for states across a broad range of domains, including war and diplomacy, economic relations, and human rights.

The term public international law embraces a wide variety legal regimes governing the conduct and relationships between states, between states and international organizations, and between entities and persons both natural and legal. Public international law defines the criteria for statehood, and legal theorists argue that it establishes states as the principal actors in the international legal system. (While the traditional view was that only states were subjects of international law, with the founding of the United Nations, that view expanded to include intergovernmental organizations. Contemporary conceptions of international law are much broader, and include the interactions such as the ones listed at the beginning of this paragraph.) Public International law also governs the outer bounds of permissible treatment of individuals by states with comprehensive international law regimes dealing with non-combatants, including prisoners of war, civilians, and refugees, as well as human rights.

A famine is a widespread scarcity of food caused by several possible factors, including, but not limited to: war, natural disasters, crop failure, widespread poverty, an economic catastrophe or government policies. This phenomenon is usually accompanied or followed by regional malnutrition, starvation, epidemic, and increased mortality. Every inhabited continent in the world has experienced a period of famine throughout history. During the 19th and 20th centuries, Southeast and South Asia, as well as Eastern and Central Europe, suffered the greatest number of fatalities due to famine. Deaths caused by famine declined sharply beginning in the 1970s, with numbers falling further since 2000. Since 2010, Africa has been the most affected continent in the world by famine. As of 2025, Haiti and Afghanistan are the two countries with the most catastrophic and widespread states of famine, followed by Sudan.

Societal collapse (also known as civilizational collapse or systems collapse) is the fall of a complex human society characterized by the loss of cultural identity and of social complexity as an adaptive system, the downfall of government, and the rise of violence. Possible causes of a societal collapse include natural catastrophe, war, pestilence, famine, economic collapse, population decline or overshoot, mass migration, incompetent leaders, and sabotage by rival civilizations. A collapsed society may revert to a more primitive state, be absorbed into a stronger society, or completely disappear.

Virtually all civilizations have suffered such a fate, regardless of their size or complexity. Most never recovered, such as the Western and Eastern Roman Empires, the Maya civilization, and the Easter Island civilization. However, some of them later revived and transformed, such as China, Greece, and Egypt.

A mercenary is a private individual who joins an armed conflict for personal profit, is otherwise an outsider to the conflict, and is not a member of any other official military. Mercenaries fight for money or other forms of payment rather than for political interests.

Beginning in the 20th century, mercenaries have increasingly come to be seen as less entitled to protection by rules of war than non-mercenaries. The Geneva Conventions declare that mercenaries are not recognized as legitimate combatants and do not have to be granted the same legal protections as captured service personnel of the armed forces. In practice, whether or not a person is a mercenary may be a matter of degree, as financial and political interests may overlap.

Realism, in international relations theory, is a theoretical framework that views world politics as an enduring competition among self-interested states vying for power and positioning within an anarchic global system devoid of a centralized authority. It centers on states as rational primary actors navigating a system shaped by power politics, national interest, and a pursuit of security and self-preservation.

Realism involves the strategic use of military force and alliances to boost global influence while maintaining a balance of power. War is seen as inevitably inherent in the anarchic conditions of world politics. Realism also emphasizes the complex dynamics of the security dilemma, where actions taken for security reasons can unintentionally lead to tensions between states.

A war god in mythology associated with war, combat, or bloodshed. They occur commonly in polytheistic religions.

Unlike most gods and goddesses in polytheistic religions, monotheistic deities have traditionally been portrayed in their mythologies as commanding war in order to spread religion. (The intimate connection between "holy war" and the "one true god" belief of monotheism has been noted by many scholars, including Jonathan Kirsch in his book God Against The Gods: The History of the War Between Monotheism and Polytheism and Joseph Campbell in The Masks of God, Vol. 3: Occidental Mythology.)

A world war is an international conflict that involves most or all of the world's major powers. Conventionally, the term is reserved for the two major international conflicts that occurred during the first half of the 20th century: World War I (1914–1918) and World War II (1939–1945). Some historians have also characterized other global conflicts as world wars, such as the Nine Years' War, the War of the Spanish Succession, the Seven Years' War, the French Revolutionary and Napoleonic Wars, the Cold War and the Global War on Terrorism.

Total war is a type of warfare that mobilizes the totality of national resources to sustain war production, blurring the line between military and civilian activities and legitimates attacks on civilian targets as part of a war without restriction as to the combatants, territory or objectives involved.

The term has been defined as "A war that is unrestricted in terms of the weapons used, the territory or combatants involved, or the objectives pursued, especially one in which the laws of war are disregarded."

This list of wars by death toll includes all deaths directly or indirectly caused by the deadliest wars in history. These numbers encompass the deaths of military personnel resulting directly from battles or other wartime actions, as well as wartime or war-related civilian deaths, often caused by war-induced epidemics, famines, or genocides. Due to incomplete records, the destruction of evidence, differing counting methods, and various other factors, the death tolls of wars are often uncertain and highly debated. For this reason, the death tolls in this article typically provide a range of estimates.

Compiling such a list is further complicated by the challenge of defining a war. Not every violent conflict constitutes a war; for instance, mass killings and genocides occurring outside of wartime are excluded, as they are not necessarily wars in themselves. This list broadly defines war as an extended conflict between two or more armed political groups. Consequently, it excludes mass death events, such as human sacrifices, ethnic cleansing operations, and acts of state terrorism or political repression during peacetime or in contexts unrelated to war.
Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).

A civil war is a war between organized groups within the same state (or country). The aim of one side may be to take control of the country or a region, to achieve independence for a region, or to change government policies. The term is a calque of Latin bellum civile which was used to refer to the various civil wars of the Roman Republic in the 1st century BC. Civil here means "of/related to citizens", a civil war being a war between the citizenry, rather than with an outsider.

Most modern civil wars involve intervention by outside powers. According to Patrick M. Regan in his book Civil Wars and Foreign Powers (2000) about two thirds of the 138 intrastate conflicts between the end of World War II and 2000 saw international intervention.

Gunboat diplomacy is the pursuit of foreign policy objectives with the aid of conspicuous displays of naval power, implying or constituting a direct threat of warfare should terms not be agreeable to the superior force.

The term originated in the 19th century, during the age of imperialism, when Western powers, especially the United Kingdom, France, Germany and the United States would use their superior military capabilities, particularly their naval assets, to intimidate less powerful nations into granting concessions. The mere presence of warships off a country's coast was often enough to have a significant effect, making the actual use of force rarely necessary.

International relations (IR, and also referred to as international studies, international politics, or international affairs) is an academic discipline. In a broader sense, the study of IR, in addition to multilateral relations, concerns all activities among states—such as war, diplomacy, trade, and foreign policy—as well as relations with and among other international actors, such as intergovernmental organizations (IGOs), international nongovernmental organizations (INGOs), international legal bodies, and multinational corporations (MNCs).

International relations is generally classified as a major multidiscipline of political science, along with comparative politics, political methodology, political theory, and public administration. It often draws heavily from other fields, including anthropology, economics, geography, history, law, philosophy, and sociology. There are several schools of thought within IR, of which the most prominent are realism, liberalism, and constructivism.