Several empires in human history have been contenders for the largest of all time, depending on definition and mode of measurement. Possible ways of measuring size include area, population, economy, and power. Of these, area is the most commonly used because it has a fairly precise definition and can be feasibly measured with some degree of accuracy.[1] Estonian political scientist Rein Taagepera, who published a series of academic articles about the territorial extents of historical empires between 1978 and 1997,[2][3][4][5] defined an empire as "any relatively large sovereign political entity whose components are not sovereign" and its size as the area over which the empire has some undisputed military and taxation prerogatives.[6] The list is not exhaustive owing to a lack of available data for several empires; for this reason and because of the inherent uncertainty in the estimates, no rankings are given.
For context, the land area of the Earth, excluding the continent of Antarctica, is 134,740,000 km2 (52,023,000 sq mi).[7]
Empires at their greatest extent
Empire size in this list is defined as the dry land area it controlled at the time, which may differ considerably from the area it claimed. For example: in the year 1800, European powers collectively claimed approximately 20% of the Earth's land surface that they did not effectively control.[8] Where estimates vary, entries are sorted by the lowest estimate. Where more than one entry has the same area, they are listed alphabetically.
^The largest peak areas of its former colonies following independence were Canada's 9.98 million km2 in 1945, the United States' 9.67 million km2 in 1899, and Australia's 7.68 million km2 in 1945.[9]
^Its successor state the USSR and its successor in turn, the Russian Federation, reached maximum extents of 22.3 million km2 in 1945 and 17.1 million km2 in 1991, respectively.[9]
^ abThe reason the Empire of Brazil is listed as having a larger area in 1889 than the Portuguese Empire had in 1820, despite Brazil having been a Portuguese colony, is that the Portuguese settlers only had effective control over approximately half of Brazil at the time of Brazilian independence in 1822.[9]
^More recent reassessment of the historical evidence, both archaeological and textual, has led modern scholars to question previous notions of the extent of the realm of the Medes and even its existence as a unified state.[20]
^The extent to which this constituted a cohesive political entity is uncertain.[29]
Timeline of largest empires to date
The earliest empire which can with certainty be stated to have been larger than all previous empires was that of Upper and Lower Egypt, which covered ten times the area of the previous largest civilisation around the year 3000 BC.[38]
^More recent reassessment of the historical evidence, both archaeological and textual, has led modern scholars to question previous notions of the extent of the realm of the Medes and even its existence as a unified state.[20] If the Median Empire never surpassed the size of the Neo-Assyrian Empire, the latter remained the largest empire the world had seen until the Achaemenid Empire surpassed it.[23][11]
Timeline of largest empires at the time
Empire
Land area during time as largest empire (million km2)[29]
^ The extent to which this constituted a cohesive political entity is uncertain. If the largest empire in the year 2100 BC was not the Indus Valley Civilisation, it was the First Intermediate Period of Egypt with an area of 0.1 million km2.
^More recent reassessment of the historical evidence, both archaeological and textual, has led modern scholars to question previous notions of the extent of the realm of the Medes and even its existence as a unified state.[20] If the largest empire in the year 600 BC was not the Median Empire, it was Late Egypt with an area of 0.55 million km2.
Largest empires by share of world population
Because of the trend of increasing world population over time, absolute population figures are for some purposes less relevant for comparison between different empires than their respective shares of the world population at the time.[39] For the majority of the time since roughly 400 BC, the two most populous empires' combined share of the world population has been 30–40%. Most of the time, the most populous empire has been located in China.[40]
Empire
Empire population as percentage of world population[41]