Initial conquest and consolidation
An empire originates in conquest of native population by a belligerent invader, for example, conquest of the Briton population of British Isles Wp→ over the millenia following evacuation of the islands by the Roman Empire Wp→. The invading nation which will later form the core of the expanding empire usually has a hierarchical military structure with a ruling family and their supporters who made up the leadership and military force of the invading horde. Typically the invading nation has a native slave or villein class, to which is added whatever part of the native population which does not flee or is killed. In the case of Britain the Anglo-Saxon invaders had not yet consolidated rule among themselves, a process which occupied the next 300 years and ended with dominion of Wessex Wp→ over the other petty Anglo-Saxon kingdoms Wp→. Thus the bedrock task of the emerging empire is control of its conquered native population and its own serfs and slaves. Initially, this is simply a matter of force, but gradually brute force becomes regulated by customary law Wp→, first embodied literally in the court of the King, but later as a specialized system of law which gradually becomes more sophisticated and generally recognized as the proper mechanism for dispute resolution. Laws at first were quite crude, as illustrated by the Germanic custom of Weregild Wp→.
The key step leading to empire is conquest of neighboring nations, which are not exterminated, but ruled. However, such nations present the danger of rebellion, thus, in addition to maintaining control over its own lower classes, the budding empire now must maintain military forces to discourage and put down rebellions by conquered nations. In the case of the example of Britain, this expansion consisted of consolidation of rule over the remainder of the British Isles, conquering first the petty Celtic kingdoms, then Wales and Ireland. Control over the entire British Isles was achieved only with the union of Scotland and England under a common king in 1707 Wp→. An attempt to conquer France Wp→ was defeated. Meanwhile, the bulk of the Anglo-Saxon aristocracy in England, and also the native aristocracy of Scotland, was replaced by Normans following the Norman conquest in the 11th century Wp→.
Exploration, war, and conquest
Having conquered neighboring nations a state builds an empire by competing with other states for dominion over other nations that are within its range. In the case of European history, the discovery of the New World and access to Asia provided a rich field for conquest of vulnerable nations and prolonged contests between imperial rivals such as Spain, France, and England, and eventually Germany and Japan. Again, each conquered nation offers the danger of rebellion, as each imperial rival offers the possibility of the breakout of armed conflict at any time. By this point, conflict is endemic, breaking into major "wars" at frequent intervals. Lands, such as North America, which are settled by pioneers from the imperial state may themselves rebel, as indeed happened in the case of the United States.
- Gore Vidal Wp→, Perpetual War for Perpetual Peace: How We Got to Be So Hated, Nation Books (March 10, 2002), trade paperback, 160 pages, ISBN-10: 156025405X ISBN-13: 978-1560254058
- Herfried Münkler Wp→, translated by Patrick Camiller, Empires: The Logic of World Domination from Ancient Rome to the United States, Polity Press (June 18, 2007), hardcover, 264 pages, ISBN-10: 0745638716 ISBN-13: 978-0745638713; trade paperback, ISBN-10: 0745638724ISBN-13: 978-0745638720