What Were the Biggest Empires in History?

Starting in the 16th century, the British followed Spain and Portugal into the Age of Exploration, establishing colonies across the Americas, Africa and Asia. Around 1840, Britain overtook the Russian Empire for the title of largest empire by land area. By the mid-19th century Britain had overtaken the Mongol empire as the largest ever. By the 1920s, maps of the British Empire showed 13.7 million square miles miles of controlled territory—nearly a quarter of the Earth’s land area.

The British Empire was also the only one in history to claim political control over an entire standalone continent (Australia). Empires typified by European colonialism differed from those that came before, Barkey says, in their size, scope, extractive focus—and effects on such a vast array of colonized cultures. “It is not that the other empires were not often also violent, but we cannot compare their forms of colonization and persecution to the traditional empires.”

Formed around A.D. 1206, when Genghis Khan unified nomadic tribes in present-day Mongolia and began a rapid territorial expansion along the Silk Road linking China, the Middle East and Europe, the Mongol Empire reached its territorial maximum—about 9 million square miles—by the late 13th century. Within its area of control, you could ride a horse from central Europe to the Sea of Japan, or from Siberia to the Indian subcontinent. The empire enabled a century of far-reaching stability and cross-cultural exchange.

China’s last imperial dynasty, the Qing dynasty (1636–1912) ruled over the greatest fraction of humanity of any in history. By around 1800, it ruled over 330 million people, amounting to 37 percent of the world’s population.

Beginning in 1978, Estonian-American political scientist Rein Taagepera published a series of articles surveying human empires and ranking them by a combination of size and duration—yielding a surprising result for the empire with the biggest historical footprint. Ancient Egypt was relatively small as empires go, but the Land of the Pharaohs had remarkable cultural and political stability, enduring for 3,000 years (c. 3100–30 B.C.) if you ignore the brief breaks between dynastic periods. According to Taagepera’s analysis it was the world’s largest empire for 1,300 years.

When the last Egyptian dynasty finally fell, it fell to the Romans, whose empire was never quite the largest, nor the most populous nor the longest-lasting. Still, “if we want to think about lasting influence,” Barkey says, “we must include the Roman Empire.”

From its origins as a republic on the Italian peninsula, the Roman Empire grew to encircle the Mediterranean and spread north into Europe and east into Asia Minor. Even after the sack of Rome in the West, the empire continued as the Byzantine Empire until A.D. 1453. Roman transit networks, including tens of thousands of miles of roads, aided the administration of the empire and provided routes for cultural transfer, including the spread of Christianity, which eventually became the empire’s official religion.

Today roughly 150 countries use some form of a civil law system, which has its roots in Rome’s imperial administration. Romance languages like Spanish and French, descended from Latin, are some of the world’s key lingua francas as they were spread across continents by later colonial and trade empires.

Although empires tend to be thought of first as areas of top-down, centralized control, Barkey’s book Empire of Difference explores how the Ottoman Empire (c. 1300-1922) achieved longevity and success at what she calls the negotiated enterprise of empire. “Empires do not really have full control,” she says. “They must depend on local power holders, local members of traders and guilds, to ensure their rule and the flow of resources and goods.”

The Ottoman Empire was ruled by Muslims in what is now Turkey but included multiple religious and cultural groups on three continents. Through skilled negotiation, the central government kept influence over a vast and culturally diverse area across many centuries and technological transformations. The Ottoman system of millet law courts developed to allow religious minorities to oversee their own internal affairs, granting autonomy though not full equality within the larger Muslim-ruled empire.