What is the average lifespan of empires?
The average lifespan of an empire, across the 61 large empires in our chart, is 260 years, and the median is 209 years. Those two numbers sit close together, but the mean is pulled upward by a handful of outliers at the top: only two empires in the set passed 1,000 years, and fifteen lasted under a century. The shortest was the First Mexican Empire at 2 years, and Napoleon's First French Empire managed just 11 years.
The question of how long empires last also depends heavily on which empires you count and how you date them. According to CT Examiner, historians say empires average about 250 years, a figure that has gained currency in popular discussion.4 Our chart's average of 260 years is close to that, though the median of 209 years is a more typical experience for any given empire. Empires founded before 500 AD lasted considerably longer, with a median of 288.5 years, against a median of just 57.5 years for the eight in the chart founded after 1800.
Has any empire lasted 1000 years?
Only two empires in our chart of 61 large empires passed 1,000 years: the Byzantine Empire, at 1,123 years, and the Holy Roman Empire, at 1,006 years counted from 800, or 844 years if dated from 962. No other empire in the set comes close.
Greek Reporter notes that the Holy Roman Empire lasted from 962 to its dissolution by Napoleon in 1806, and describes it as a Germanic empire despite its name, heavily tied to the papacy throughout much of its existence.1 The Byzantine Empire's 1,123-year run is described by one account as covering everything from periods of maximum territory under Justinian I in the 6th century, through near-collapse and recovery, to a final decline ending when Constantinople fell to the Ottoman Turks in 1453.5 The question of how long did the Roman Empire last depends on where you draw the line: Wikipedia's dates for the western empire alone give 421 years (27 BC to 395), placing it 11th of 61 in our chart.
Why did the Byzantine Empire last so much longer than other empires?
Several structural factors help explain why the Byzantine Empire lasted 1,123 years, far beyond the 209-year median for large empires. One account points directly to Constantinople itself: the city's location on the Bosphorus Strait, surrounded by sea on three sides, made it a natural fortress, and the choice of that site may have determined the lifespan of the empire.5 The Western Roman Empire, lacking such a capital, collapsed in 476, just 81 years after the East-West division, while the East survived for nearly a millennium more.
The empire's longevity was also a product of repeated adaptation rather than unbroken strength. It came close to ending many times, losing its southern territories to the rise of Islam in the 7th and 8th centuries, suffering the blow of the Fourth Crusade, and facing the Seljuk Turks before the final Ottoman conquest.5 Edward J. Watts, in his 2025 book reviewed by the Los Angeles Review of Books, offers three overlapping answers for Rome's exceptional duration: the Romans' readiness to admit others into their society, their openness to outside ideas, and their facility for adaptation.6 Those qualities, carried forward into the Byzantine period, help explain how an empire on the verge of collapse could recover and endure across more than eleven centuries.
What is the 250 year rule for empires?
The 250-year rule holds that empires rise and fall on an average cycle of roughly 250 years. According to CT Examiner, historians say empires average about 250 years, a figure tied to broader patterns of expansion, overextension and decline visible across many cases.4 Our chart's average lifespan of an empire across 61 large empires is 260 years, and the median is 209 years, both broadly consistent with that rule of thumb.
The figure is a central tendency, not a law. Fifteen empires in the chart lasted under a century, and two passed 1,000 years. Eikleaf identifies recurring economic signals that tend to precede imperial collapse, including currency erosion, rising frontier costs, elite tax capture and reform paralysis, and argues that in each case these signals came before the military or political events history names as causes.3 That pattern suggests the 250-year figure reflects how long it typically takes for those structural pressures to overwhelm an empire's capacity to respond, rather than any fixed political clock.
Did larger empires tend to collapse faster than smaller ones?
Larger empires did not tend to last longer: the data in our chart point the other way. The 10 largest empires by peak area lasted a median of 179 years, below the 209-year median for all 61 empires in the set. The Mongol Empire, the second largest at its peak at 24.0 million square kilometres, lasted just 162 years.
Eikleaf's analysis of imperial collapse identifies frontier cost inflation as one of five recurring economic signals before a fall, noting that as the perimeter grows, it becomes too expensive to maintain.3 A larger empire faces that pressure sooner and more acutely. World Atlas makes a related point about the Ottoman Empire, arguing that its decentralised governance helped it manage vast and diverse territories in its early and middle periods, but that the same decentralisation later created difficulties when nationalist movements challenged imperial cohesion.2 Size, in other words, created administrative and military burdens that tended to shorten rather than extend an empire's life.