When an Empire Divides: Ancient Lessons on Ever-Menacing Inequality
What happens when an empire grows too large? When the central apparatus gets richer at the expense of outer regions, and inequality becomes structural? This is the question asked by Guido Alfani (Bocconi), Michele Bolla (Cambridge) and Walter Scheidel (Stanford), who in a recent paper. (A comparison of income inequality in the Roman and Chinese Han empires) published in Nature Communications have reconstructed with surprising quantitative tools the level of economic inequality in two of the greatest civilizations in history: the Roman Empire and the Chinese Han Empire.
The results speak for themselves. The Gini index, which measures income inequality, from 0 (perfect equality) to 1 (maximum inequality), is estimated at 0.46 for Rome and 0.48 for Han China. High values, comparable to those of some very unequal contemporary societies, and higher than those of many medieval European societies.
But that is not all. Perhaps the most powerful indicator is the “inequality extraction ratio”: a measure of how close a society approaches the theoretical maximum of sustainable inequality (i.e., how much the elite can extract resources before the social base collapses). Here the gap is stark: Rome 69 percent, Han 80 percent, while the Aztec Empire (included as a comparison) reaches a shocking 89 percent. “A more extractive society is also more fragile,” explains Alfani, director of Bocconi's Dondena Center. “And history shows that.”
Elites at the center, provinces at the margin
To get to these results, the authors reconstructed not only per capita income levels (using urbanization for Rome and population density for Han as proxies), but also detailed “social tables” for each region, by combining historical data, censuses and comparative models.
The picture that emerges is fascinating. In the Roman Empire, three provinces outside Italy exceeded 2.5 times subsistence income, a sign of relatively widespread prosperity. In contrast, in Han China only the Sili region around the capital Chang'an reached similar levels, leaving the rest of the country in a condition of relative impoverishment. This imbalance was due to precise political decisions: while Rome integrated local elites and incentivized urban development in the periphery, the Han rulers feared local autonomy and proceeded to forcibly remove wealthier families to the capital at least six times in one century.
“These forced migrations,” Alfani explains, “were meant to strengthen the center and neutralize intermediate powers. But in the long run this impoverished the provinces, exacerbating territorial inequalities.”
Tax, military and bureaucracy: the mechanics of extraction
The paper goes into the details of the tax mechanisms: Rome levied variable taxes according to the history and economic capacity of the provinces (Italy was even exempt from land tax), while the Han imposed a uniform rate throughout the Empire, notionally fair but in reality impervious to real disparities.
In Rome, moreover, military expenditure served as a redistributive tool: legions were often stationed in border provinces, transferring part of the public resources there. In contrast, the Han Empire, with a less professionalized and less distributed army, favored the bureaucracy, composed, however, of well-paid officials concentrated in the Sili, accentuating the center-periphery divide.
A world of few rich and many poor
The data on income shares are impressive: the richest 5% held 37% of income in Rome, and 42% in Han China, while the poorest 50% no more than 25% and 24% respectively. A pyramidal world, where wealth rose upward like incense to the gods.
Yet, in spite of all this, Rome still managed to hold on for centuries, while Han China was engulfed in a political crisis as early as a few years after 2 AD, the year analyzed in the study. Chancellor Wang Mang, who came to power in 9 AD, tried to redistribute land and introduce a 10 percent income tax for skilled professions. “It was one of the first real social reforms in history,” Alfani notes. But it failed. The elites opposed it, the provinces were already at the point of exhaustion, and the countryside exploded with the “red eyebrow” (Chimei) revolts. The Han Empire never fully recovered.
Today as yesterday? Lesson for modern democracies
What does all this teach us? “Large territorial inequalities are not just a problem of the past,” Alfani reflects. “In Britain, the imbalance between London and the industrial north played a decisive role in the vote for Brexit. And in Italy, in France, in the United States, we detect similar signs: inequality between regions reduces the social cohesion within the state.”
The risk is not only economic, but political. Over-extraction without redistribution can trigger instability, anger, disaffection. In today’s world confronted with new inequalities, be they technological, climatic, generational, the past offers not recipes but warnings. And sometimes, as in this case, it does so with the firm voice of history and the precision of a quantitative model.