Sir John Glubb studied the lives of empires:
If we desire to ascertain the laws which govern the rise and fall of empires, the obvious course is to investigate the imperial experiments recorded in history, and to endeavour to deduce from them any lessons which seem to be applicable to them all.
The word ‘empire’, by association with the British Empire, is visualised by some people as an organisation consisting of a home-country in Europe and ‘colonies’ in other continents. In this essay, the term ‘empire’ is used to signify a great power, often called today a superpower. Most of the empires in history have been large landblocks, almost without overseas possessions.
We possess a considerable amount of information on many empires recorded in history, and of their vicissitudes and the lengths of their lives, for example:
This list calls for certain comments.
(1) The present writer is exploring the facts, not trying to prove anything. The dates given are largely arbitrary. Empires do not usually begin or end on a certain date. There is normally a gradual period of expansion and then a period of decline. The resemblance in the duration of these great powers may be queried. Human affairs are subject to many chances, and it is not to be expected that they could be calculated with mathematical accuracy.
(2) Nevertheless, it is suggested that there is suf?cient resemblance between the life periods of these different empires to justify further study.
(3) The division of Rome into two periods may be thought unwarranted. The ?rst, or republican, period dates from the time when Rome became the mistress of Italy, and ends with the accession of Augustus. The imperial period extends from the accession of Augustus to the death of Marcus Aurelius. It is true that the empire survived nominally for more than a century after this date, but it did so in constant confusion, rebellions, civil wars and barbarian invasions.
(4) Not all empires endured for their full lifespan. The Babylonian Empire of Nebuchadnezzar, for example, was overthrown by Cyrus, after a life duration of only some seventy-four years.
(5) An interesting deduction from the ?gures seems to be that the duration of empires does not depend on the speed of travel or the nature of weapons. The Assyrians marched on foot and fought with spears and bow and arrows. The British used artillery, railways and ocean-going ships. Yet the two empires lasted for approximately the same periods.
There is a tendency nowadays to say that this is the jet-age, and consequently there is nothing for us to learn from past empires. Such an attitude seems to be erroneous.
(6) It is tempting to compare the lives of empires with those of human beings. We may choose a ?gure and say that the average life of a human being is seventy years. Not all human beings live exactly seventy years. Some die in infancy, others are killed in accidents in middle life, some survive to the age of eighty or ninety. Nevertheless, in spite of such exceptions, we are justi?ed in saying that seventy years is a fair estimate of the average person’s expectation of life.
(7) We may perhaps at this stage be allowed to draw certain conclusions:
(a) In spite of the accidents of fortune, and the apparent circumstances of the human race at different epochs, the periods of duration of different empires at varied epochs show a remarkable similarity.
(b) Immense changes in the technology of transport or in methods of warfare do not seem to affect the life-expectation of an empire.
(c) The changes in the technology of transport and of war have, however, affected the shape of empires. The Assyrians, marching on foot, could only conquer their neighbours, who were accessible by land — the Medes, the Babylonians, the Persians and the Egyptians.
The British, making use of ocean-going ships, conquered many countries and subcontinents, which were accessible to them by water — North America, India, South Africa, Australia and New Zealand — but they never succeeded in conquering their neighbours, France, Germany and Spain.
But, although the shapes of the Assyrian and the British Empires were entirely different, both lasted about the same length of time.