One of the most contentious debates about the city of Rome concerns its most basic characteristic: its size. All scholars seem to agree that ancient Rome was big, at least twice the size of any other city at the time. They also tend to agree that it was the largest city before the modern era, meaning up until the last 200 years or so. But beyond these basic order-of-magni-tude estimates, there is no agreement on just what the actual population was. Reasonable estimates offered by various scholars range from a couple hundred thousand to several million. There may have been some non-Western cities with comparable populations, but the available data for these is unreliable. Ancient Rome was, at any rate, clearly the largest Western city until recently.
Nowhere does an ancient source give us an actual population figure for the city at its height. Instead, what we have are several separate bits of data from which scholars have attempted to extrapolate or estimate the population. Three key pieces of hard data have to do with the number of people who received monthly handouts of free grain from the government, a set of statistics that give total numbers of dwellings in the city, and estimates that are based on the area of the city.
One ancient source states that in 5 bc, 320,000 inhabitants of the city received the free monthly grain dole. To be eligible for this dole, you had to be three things: an adult, a male, and a citizen. If there were this many adult, free males, one can perhaps double this number to account for women, add the same number again for children, and then add an estimate for the number of slaves. Such a calculation would yield a population estimate well in excess of one million people. There are many problems with such a calculation, however. Did all citizens who were eligible collect the dole? How accurate were the lists? Also, as with cities in many eras, ancient Rome seems to have had a population that included large numbers of young males who left their family farms seeking fame.
Fortune, or simply adventure in the big city. At this time in Roman history, there may well have been large numbers of veterans swelling the numbers of urban dwellers as well. All these factors indicate that the number of women and possibly of children may have been much less than the number of men, suggesting a lower overall population number. Estimating the number of slaves also involves considerable guesswork; therefore, population estimates that begin extrapolating from the 320,000 grain dole recipients can reasonably vary quite widely.
A second piece of information that might shed light on the number of inhabitants is a document called the Regionary Catalog, dating to the fourth century ad, which lists the total number of different types of residential buildings that existed in the city at this time. According to the Regionary Catalog, Rome at this point had 1,782 domus (private homes) and 43,580 apartment buildings. Using these two bits of information, one can create an estimate of what the population of the city might have been. Obviously, much depends on one's assumptions about how many people on average lived in a house and in an apartment building. If one assumes 100 residents in a typical apartment building, then one will arrive at a huge estimate for Rome's population, but if one chooses a small number, the result will be dramatically different.
A final strategy for estimating Rome's population rests upon the fact that it is known fairly precisely how large the occupied area of the ancient city was. The Aurelian Wall enclosed approximately 1,370 hectares. Using this piece of information, it should be possible to estimate the density of inhabitants per acre and thereby calculate the total population. A complicating factor for this type of calculation is taking into account what percentage of the area within the walls was used by nonresidential purposes such as streets, open spaces, gardens, and public buildings. The density of large modern cities can perhaps be used as a partial guide to estimating density figures for ancient Rome.
An enormous amount of ink has been spilled by scholars using these various methods and arguing with one another over whose estimates are most accurate. The grain dole approach tends to yield very high numbers, while the density method suggests a lower range, with the Regionary Catalog data spanning both extremes. In the end, most estimates for Rome's population seem to cluster around one million at its height (first century BC through second century ad). The debates and uncertainty surrounding such a basic statistic as the size of ancient Rome illustrate how difficult it is to study ancient cities when so much data is lacking.
The estimate of around one million inhabitants, if reasonably accurate, makes Rome unique because no other Western city seems to have reached this size for nearly 2,000 years—not until Paris and London achieved this population in the nineteenth century. The famous cities of the Italian Renaissance rarely reached 100,000 inhabitants. Rome's enormous population also makes it a particularly relevant and interesting object of study for us today because the ancient Romans had to struggle with certain types of urban problems, such as crowding and sanitation, that no other people have had to contend with until recently. Therefore, Rome is the original prototype for all great modern cities, and by studying how the Romans faced these problems, we can perhaps gain some insights into how to handle them today.
World History
