An empire is a political unit composed of a number of territories, peoples, or nations which is ruled by a single supreme authority.
Characteristics of an empire
Empires are all individual in character, having been formed in widely different times under widely different political structures. They are so differentiated that the term Empire is more an abstract idea of an accumulation of nations under a single authority than it is a concrete form of government.
For example, the Mongol Empire was an expanse of sparsely populated nations, tribes and empires that were discovered and conquered by force, whereas the British Empire was a dispersed and diverse collection of nations that were discovered, conquered, coerced, bought, or simply administered by the British crown.
The calculation of the land area of a particular empire is controversial: The area of Northern Siberia is not included in the size of the Mongol Empire because it was unpopulated, but is included in Russian Empire in the map. But the area of Northern Canada, which was only very sparsely populated, is included in the land area calculation of the British Empire, and so is the case with Russian Empire including Northern Siberia in the map even though it was unpopulated. The Mongol Empire had a peak population of 130 million, the Russian Empire of 125 million.
