Roman Era Population Numbers

Another one of my old Sardis Verlag blog posts. Here I want to try to give the reader some population numbers for the territories depicted on the Imperium Romanum 211 AD map.

Originally this text was posted in German only on our old homepage in December 2014. Now I’ve finally found the time to translate it into English. When I begun writing this lines I intended to support the Roman Empire map with a lot of statistical data, discussing all kind of related numbers like army size or as in this post, population numbers. In my original plan this text should have been followed by another post or chapter discussing population numbers for some extraordinary and more common cities among the 1200 that are depicted on my map throughout the Empire

It is an exciting and commonly asked question what number of people actually lived within ancient cities and states. A question that is unfortunately very hard to answer with some precision. 

Just as other ancient states the Romans regularly conducted a census, in which the complete population and their property were registered. Originally the intent was to know the states military capacity, but during the Empire the data was mainly collected for purposes of taxation. Sadly, the results of this labors are only punctually known to us. Fragments of census lists from Roman Egypt or an occasional population number of certain cities in the works of ancient authors or inscriptions is all that has survived after two millennia. Most valuable for our understanding of Roman demography is a long row of census results in various primary sources. Each one giving us the total number of Roman citizens from the 3^rd century BCE until the reign of emperor Claudius. Thus scholarly publications and the surrounding debate often concentrate on the population of Roman Italy, exceptionally relevant as a reference scale for other provinces and estimates of the total population size.

However all of these numbers have their problems. It most cases it is simply unclear which groups were included in the published number (all inhabitants or just full citizens, etc.). In the case of cities the population number usually includes the entire territory of a city state, which extent is quite often not very well known, not just the actual urban core that can be more easily traced by archaeology. Especially in rural areas we should always be aware that the term city can have a different meaning to us than for Greeks or Romans. For them a “city”, Polis or Civitas, was the body of all its citizens, not only those living in the walled center. Thus population numbers for this class can easily differ by a factor of 4, in ancient sources, as well as modern literature, depending on the definition used by the author.

For Italy the previously consistent number of Roman citizens makes a big jump from 1 million in 70 BCE, when the last republican census was completed, to 4 million after the first census of emperor Augustus in 28 BCE. Between both numbers lies an epoch of turmoil and civil wars the accompanied the fall of the Republic and birth of the Empire. A factor of four in just 42 years is to large to be explained by natural population growth alone. It is not unlikely that under Augustus simply a larger number of Romans was included in this number than before, like women and children. This is however not necessary to explain the difference, since during this time citizenship was granted to the inhabitants of entire cities and regions, like the former province Gallia Cisalpina, which became a part of Italy.

The discussion is dominated by two scenarios, described in detail in the articles Roman population size: the logic of the debate from W. Scheidel and Ancient statistics and the rise of demography: a historiography of demographic debate on Roman Italy  from S. Hin [1]. The so called low count is based on the assumption that republican numbers just included military aged males, while imperial numbers also include women and children. For the proponents of the high count the systematic didn’t change. Consequently both lead to greatly different population sizes for the peninsula during the early Empire. A great number of important factors are poorly known, such as the number of citizens outside of Italy, and there are good arguments of consistency for (or against) both variants. Summed up, the majority of scholars seem to agree that the low count scenario is more plausible.

In recent times a convincing third variant, the middle count, has become popular again. It is explained in another article from Hin. According to the middle count Augustus and his successors counted all persons sui iuris of both sexes and all ages, meaning all persons in full legal control over their actions and decisions, for his published numbers. However this interpretation causes new uncertainties when calculating total population numbers.

Archaeology too, can only contribute answers in a limited way. Few regions are surveyed well enough to surely know the full number of settlements and their size. Even when buildings are excavated the number of inhabitants can only be guessed with some significant error. Known cities can only rarely be completely examined, so that the size and density of living quarters within their walls are hard to determine. However the accumulation of data over centuries of archaeological research, as well as the possibilities of modern remote sensing techniques and geophysical methods, make it increasingly possible to study extended areas in previously unknown detail.

These uncertainties and problems should always be kept in mind when looking at the following numbers for the Roman Empire and some neighboring societies.

Imperium Romanum

Global Estimates

For the Roman Empire estimated population sizes can typically be found for two points in time, the final year of Augustus reign (14 CE) and 165 CE. The first date because of the census data discussed above, while the latter is generally seen as the Empire’s demographic peak. In 165 CE the Antonine Plague begun to spread throughout the Roman realm. Their effects are not fully understood, but a considerable death toll is highly likely, while the chaotic decades during the great crisis of the 3rd century make any reliable simulation of the further development nearly impossible. 

A low count estimate for the entire Empire for first attempted by Julius Beloch, one of the pioneers of this field. For 165 CE it gives us a population size of about 60 million people. Contrary, estimates following the high count logic can surpass the 100 million mark. The contemporary and roughly equally sized Chinese Han Empire, for which complete census data has survived, was inhabited by about 60 million people too.

In more recent times Scheidel [2] made a new estimate with a low count based approach. He adopted the population numbers from Frier [3], who used McEvedy and Jones [4] numbers for 14 CE and continued them to 165 CE. Scheidels results are given in the table below. The population density is only calculated from the arable parts of each province, in Egypt for example only the 30.000 km² of the Delta and Nile valley, excluding the extensive deserts. Numbers in parenthesis include the necessary modifications if the middle count model is accepted for Italy.

Samples – The Roman population of Germany 

For some regions there are good estimates based on sufficient amounts of archaeological data that can be used to test the plausibility of such global numbers. A study made by K.P. Wendt and A. Zimmermann examines the population density in the formerly Roman parts of modern Germany until the mid 2^nd century CE. The authors made a digital copy available form researchgate.net. In their approach they used high quality data about settlement density from very well or completely surveyed areas, such as coal strip mines in North Rhine Westphalia, and scaled it up to cover greater areas, classified by archaeological maps.

For the Rhineland, approximately between the cities of Augusta Treverorum in Gallia Belgica and Colonia Ulpia Traiana in Germania Inferior, they calculated a population density of 11-18 per km², a number in good agreement with the estimates given above for this region.

No similarly detailed archaeological maps were available to the authors for the entirety of Roman Germany. Especially the lack of a detailed regional study for the Roman era usage of the more mountainous areas was criticized. Thus a greater error has to be expected. The resulting total population density is between 4.8 and 10 people per km², which is further decreased to 4 to 9 per km² when the Rhineland is excluded. This significantly lower value is caused by a number of large, but only sparsely inhabited regions, like parts of Raetia, the Swabian Jura or Black Forest. The two latter ones were part of an territory called Agri Decumates by Roman authors. The triangle between the Rhine, Main and Danube. The Agri Decumates were almost uninhabited during the 100 year time span preceding Roman occupation, before being re-colonized by people mainly from Roman Gaul. Thus a lower population density compared to the other parts of Germania Superior has to be expected. Despite all his the numbers still fit, if compared with the neighboring lands along the Danube.

Garamantes

Since the turn of the century the territory of the former kingdom of the Garamantes (map grid E7) has come into the focus of archaeological research. Just as many other desert areas it was barely noted before. Additionally census data from the Italian colonial period is available. It was collected in the 1930ties, when local living conditions were still similar to ancients times, before the introduction of modern technology. The kingdom flourished in the first centuries of our era, thus the following numbers are also for this period. 

The oases of modern Fezzan formed the core of the Garmantian kingdom and included its capital Garama. D. Mattingly [5] assumes that a population of 50.000 to 100.000 people did live there, compared to only 30.000 registered by the Italian census. The significantly higher value for the ancient period is justified by the results of their surveys, showing a great number of foggaras (known as qanats in the middle east) dated to that period. With them the Garamentes could collect water from numerous, by then still active, aquifers that have fallen dry in alter periods. Thus they could still irrigate greater tracts of land than their successors.

D. Liverani [6] assumes that a population of about 4.000 people had lived in the oasis group around modern Ghat, likely to be identified with ancient Rapsa (as on my map), in the south western edge of the kingdom. A number in good agreement with the Italian census data.

Germania

For Germania Magna, G. Stangl [7] also estimated the members of the various tribes between the Rhine and the Vistula based on the available archaeological data. He calculated the tribal territories from the spatial distribution of found artifacts. Areas in which a high concentration of finds were made alternate with almost empty stripes. The tribal territories were then multiplied with a possible local population density, also implicated by the number of finds. His calculations were made for the political landscape around 50 CE, but he assumes that the total population size was relatively constant during the first two centuries of our era. His numbers sum up to 1.6 to 2.4 million people in total.

Additional Literature, not linked in the text

[1] S. C. Hin, Ancient statistics and the rise of demography: a historiography of demographic debate on Roman Italy, in: Haake, M., Harders, A.-C. (Hrsg.): Die politische Kultur und soziale Struktur der römischen Republik : Beiträge einer internationalen Konferenz aus Anlaß des 70. Todestages von Friedrich Münzer, Münster, 20.–22. Oktober 2012, Franz Steiner Verlag (2016).

[2] W. Scheidel, Demography, in: W. Scheidel, I. Morris, R. Saller (eds.), The Cambridge economic history of the Greco-Roman world, Cambridge University Press (2007), 38-86.

[3] B. W. Frier, Demography, in: A. K. Bowman, P. Garnsey, University of Cambridge, D. Rathbone (eds.), The Cambridge Ancient History Volume 11. The High Empire, AD 70–192, Cambridge University Press (2000), 787-817.

[4] C. McEvedy, R. Jones, Atlas of World Population History, Puffin (1978).

[5] D. J. Mattingly, The Garamantes: the First Libyan State, in The Libyan Desert: Natural Resources and Cultural Heritage, Society for Libyan Studies Monograph number 6 (2006).

[6] M. Liverani (ed.), Aghram Nadharif. The Barkat Oasis (Sha 'abiya of Ghat, Libyan Sahara) in Garamantian Times, AZA Monographs Vol. 5. Florence: All'Insegna del Giglio (2005).

[7] G. Stangl, Bevölkerungsgrößen Germanischer Stämme im 1. Jh. n.Chr., in: K. Tausend, Im Inneren Germaniens: Beziehungen zwischen den Germanischen Stämmen vom 1. Jh. v. Chr. bis zum 2. Jh. n. Chr., Geographica Historica 25, Franz Steiner Verlag (2009).