政府 | 定義、歴史、事実 | ブリタニカ

Government | Definition, History, & Facts | Britannica Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos government Introduction Primitive government Agricultural society The spread of civilization Greece The city-state Monarchy, oligarchy, democracy Rome The republic The empire The Middle Ages Dissolution and instability Feudalism The rise of law and the nation-state Emergence of the modern world The rise and fall of absolute monarchy Representation and constitutional monarchy The American and French revolutions Nationalism and imperialism 20th-century models Communism and fascism Liberal democracy Prospects in the 21st century References & Edit History Related Topics Images At a Glance government summary Related Questions What is imperialism in history? Does imperialism still exist today? Did imperialism cause World War I? What is the divine right to rule in a monarchy? What is democracy? print Print Please select which sections you would like to print: Table Of Contents CITE verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook X URL https://www.britannica.com/topic/government Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Cornell Law School - Legal Information Institute - Government Openstax - American Government 4e - What is Government? Scholars at HARVARD - Government and economics: An emerging field of study (PDF) GW Institute of Public Policy - Government and Governance UShistory.org - The Purposes of Government Social Sciences Libretexts - What is Government? LiveScience - What Are the Different Types of Governments? University of Central Florida Pressbooks - American Government (2e � Second Edition) - What is Government? Britannica Websites Articles from Britannica Encyclopedias for elementary and high school students. government - Children's Encyclopedia (Ages 8-11) government - Student Encyclopedia (Ages 11 and up) government Ask Anything Quick Summary Homework Help Written by Hugh Brogan Professor of History, University of Essex, Colchester, England. Author of Longman History of the United States of America and others. Hugh Brogan Fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Mar. 13, 2026 • History Britannica AI Ask Anything Quick Summary Table of Contents Table of Contents Quick Summary Ask Anything Top Questions What is a government? Why do countries need governments? What are some different types of governments? Who makes decisions in a government? How are leaders chosen in different government systems? What are some ways citizens can participate in their government? Show more Show less government , the political system by which a country or community is administered and regulated. Most of the key words commonly used to describe governments—words such as monarchy , oligarchy , and democracy —are of Greek or Roman origin. They have been current for more than 2,000 years and have not yet exhausted their usefulness. This suggests that humankind has not altered very much since they were coined. However, such verbal and psychological uniformity must not be allowed to hide the enormous changes in society and politics that have occurred. The earliest analytical use of the term monarchy , for example, occurred in ancient Athens, in the dialogues of Plato ( c. 428– c. 348 bce ), but even in Plato’s time the term was not self-explanatory. There was a king in Macedonia and a king in Persia , but the two societies, and therefore their institutions, were radically different. To give real meaning to the word monarchy in those two instances, it would be necessary to investigate their actual political and historical contexts . Any general account of monarchy required then, and requires today, an inquiry as to what circumstances have predisposed societies to adopt monarchy and what have led them to reject it. So it is with all political terms. This article discusses the historical development of governments, primarily in the societies of the West. ( See also political science ; political system ; state .) Primitive government Agricultural society So long as humans were few, there was hardly any government. The division of function between ruler and ruled occurred only, if at all, within the family . The largest social groups, whether tribes or villages, were little more than loose associations of families, in which every elder or family head had an equal voice. Chieftains , if any, had strictly limited powers; some tribes did without chieftains altogether. This prepolitical form of social organization may still be found in some regions of the world, such as the Amazonian jungle in South America or the upper Nile River valley in Africa. The rise of agriculture began to change that state of affairs. In the land of Sumer (in what is now Iraq) the invention of irrigation necessitated grander arrangements. Control of the flow of water down the Tigris and Euphrates rivers had to be coordinated by a central authority , so that fields could be watered downstream as well as farther up. It became necessary also to devise a calendar , so as to know when the spring floods might be expected. As those skills evolved, society evolved with them. In early Sumer, it is reasonable to assume, the heads of the first cities , which were little more than enlarged villages, only gradually assumed the special attributes of monarchy —the rule of one—and the village council only gradually undertook a division of labour , so that some specialized as priests and others as warriors, farmers, or tax gatherers (key figures in every civilized society). As organization grew more complex, so did religion : an elaborate system of worship seemed necessary to propitiate the quite elaborate family of gods who, it was hoped, would protect the city from attack, from natural disaster , and from any questioning of the political arrangements deemed necessary by the ruler group. Unfortunately—but, given human nature , inevitably—the young cities of Sumer quarrelled over the distribution of the rivers’ water, and their wealth excited the greed of nomads outside the still comparatively small area of civilization (a word deriving from the Latin word for city, civitas ). War , perhaps the most potent of all forces of historical change, announced its arrival, and military leadership became at least as important an element of kingship as divine sanction. It was to remain so throughout the long history of monarchy: whenever kings have neglected their military duties, they have endangered their thrones. The wars of Sumer also laid bare another imperative of monarchy—the drive for empire , arising from the need to defend and define frontiers by extending them and the need to find new means to pay for troops and weapons, whether by the plunder of an enemy or by the conquest of new lands, or both. The spread of civilization The history of Old World monarchy, and indeed of civilization, was to consist largely of variations on the patterns mentioned above for four or five millennia. Trade contacts carried the principles of civilization to Egypt and to India (China, like the pre-Columbian societies of the Americas, seems to have evolved independently). And everywhere, once the social order was established, the problem of defending it became paramount . Although the broad zone of civilization spread steadily, so that by the reign of the Roman emperor Trajan (98–117 ce ) there was a continuous band of civilized societies from Britain to the China Sea , it was always at risk from the barbarian nomads who roamed the great steppelands of central Eurasia. These nomads had retained the loose and simple institutions of primitive societies, but they had in other ways evolved as rapidly and successfully as the cities themselves (and partly under the cities’ influence). The steppe was horse country, and, armed with bows and arrows , the barbarians of all epochs possessed marvelously swift and deadly light cavalry. They fought constantly among themselves for pasturage, and the losers were forever being driven west, south, and east, where they often overcame any defenses that the farms and cities of civilization could muster against them. Explore Britannica Premium! Trusted knowledge for those who want to know more. SUBSCRIBE Yet the nomads’ military challenge was never sufficient to overturn civilization entirely. Either the invaders would overrun the settled lands and then adopt civilized customs, or the frontier defenses would prove strong enough to hold them off. There were even long periods of peace, when the barbarian threat was negligible. It was at such times that the spontaneous ingenuity of humankind had greatest play, in politics as in everything else. But it is noteworthy that, in the end, what may be described as the ancient norm always reasserted itself, whether in Europe, the Middle East , India, or China. Military crises—barbarian invasions, civil wars , or war between competing polities—recurred, necessitating the strengthening of government. The effort to secure a measure of peace and prosperity requ