To the Last Man: Demography and the Roman Army’s Darkest Hour

A little while ago, I wrote about how the Second Punic War lasted so long that many of the men in Hannibal’s army would have had more to fear from old age than their opponents, the Romans. This week, I’m going to look at the war’s demographics from the Roman perspective. On the bright side, old age was probably a minor concern for Roman men during the war. Unfortunately, this was because a very great number of them died in decidedly less natural ways.

During the first few years of the Second Punic War, the Roman Republic suffered losses on a scale proportional to those of the Soviet Union during World War II. As many as a third of all males eligible for military service died during the first three years of the war. How did the Roman Republic not only survive such losses and win the war, but emerge strong enough to rapidly overrun the rest of the Mediterranean in the years following the conflict? 

The Roman Military System Before the Second Punic War

During the mid-Republic, the Roman army consisted of two types of soldiers. The first were Roman citizens, drawn from the regions around the city of Rome. The second consisted of Roman allies, from cities in the rest of Italy. In the century before the Second Punic War, Rome had subjected these cities and forced them to provide men for its armies. Typically, Roman citizens made up half of each Roman army, and the other half came from Roman allies. 

Roman infantry of the Second Punic War

To qualify to service in the Roman legions, a Roman citizen had to be male (a requirement for citizenship) and own at least 400 denarii worth of property (for reference, a legionary in this period made about 120 denarii per year). Men of this social class between the ages of 16 and 46 were called iuniores. Once called up, the iuniores might serve for up to sixteen campaigns, which could equate to many years away from home. 

The census of 224 BCE, taken shortly before the Second Punic War, reported 273,000 Roman citizens. (This would have translated to close to a million Roman men, women, and children). Polybius, our main source for the period, estimates that at the same time, about 231,000 were sufficiently young and propertied to be iuniores. However, the census, being highly concerned with military manpower, typically undercounted the number of poor Romans not eligible for military service. These men, with wealth less than 400 denarii, were known as the proletarii, and numbered in the tens of thousands. Historian and demographer P.A. Brunt estimates that the real total of citizens would have been a bit over 300,000, and more recent historians like Walter Scheidel have argued that the number was greater still. Yet for military purposes, the Roman state likely viewed the exact number of proletarii as fairly unimportant, since they could not serve in the legions.

The Early Years of the Second Punic War (218-209 BCE)

So how did these 231,000 iuniores fare during the first years of the Second Punic War? Not very well. The invasion of the Carthaginian general Hannibal resulted in many catastrophic Roman defeats and horrifying casualties. Below is a partial list of major engagements of the war, as well as the Roman dead. 

  • 218 BCE
  • Battle of the Ticinus – 2,000
  • Battle of the Trebia – 20,000
  • 217 BCE
  • Battle of Geronium – 8,000
  • Battle of Lake Trasimene – 20,000
  • 216 BCE
  • Battle of Cannae – 48,000 (plus 10,000 iuniores executed after the battle) 
  • Battle of Silvia Litana – 15,000 
  • 212 BCE
  • Battle of Capua – 1,500
  • Battle of Silarus – 15,000 
  • Battle of Herdonia – 16,000
  • 211 BCE
  • Battle of the Upper Baetis – 10,000
  • 210 BCE 
  • Second Battle of Herdonia – 10,000 
  • Total: 165,500 battle deaths

Assume that half of the battle deaths were iuniores (since they made up half of Roman armies) and we have an estimate of 92,750 iuniores battle deaths during the first nine years of the Second Punic War. Rome began the war with about 231,000 iuniores, and during the first nine years, about another 70,000 would have aged into military service. Of these 301,000 men, nearly a third died in battle against the Carthaginians. 

Please note that this is certainly a huge undercount, since the above list excludes both skirmishes and all battles for which the sources give no numbers of Roman dead. Furthermore, Roman women and children would also have died in the war, as Hannibal’s Carthaginian army ravaged the Italian countryside. The Roman census (admittedly an imprecise measure) reflects the immense carnage of the war. In 208, the census reported 137,108 Roman citizens, down from 273,000 in 224. 

Roman census totals between 224 and 188. We’ll talk more about these later years farther down.

What is still more incredible than the vast devastation of the war, was the determination with which Rome continued to fight. Between 214 BCE and the end of the war in 202, the Romans kept an average of almost 90,000 men (plus allies) in the field (this is according to P.A. Brunt’s Italian Manpower, the definitive book on the matter). Many of these men remained abroad for years at a time. The army of Scipio Africanus, for example, fought in Iberia for seven years, from 211 to 205. In all likelihood, fewer than 100,000 iuniores remained at home during the war, or less than a third of the pre-war population of men eligible for military service. 

To make up for its shattered manpower, Rome resorted to more unconventional tactics. On at least two occasions, Rome recruited slaves to fight in exchange for freedom. Another time, boys aged below 16 volunteered to fight (a rare example of child soldiers in the pre-modern world). 

I think it is worthwhile to step back in imagine what life must have been like on the home front. Among propertied people between ages 16-46, women would have outnumbered men by a proportion of 3-1. Women undoubtedly deserve a huge amount of credit in keeping the war effort afloat. Ancient sources describe wealthy women donating their fortunes to the war chest, and others say that widows and families were forbidden to mourn their dead family members. The still more important job of keeping Rome’s businesses and farms in operation would have fallen to women as well.

Despite the heroic efforts of Rome’s women to help the state maintain its enormous mobilization, even their efforts could not prevent another serious problem – a plummeting birth rate. If roughly a third of all iuniores had died in the war, and another third campaigned away from home for years at a time, the birth rate for the propertied classes must have dropped significantly The lack of births between 218 BCE and 202 would not have been an especially dire problem at the height of the war, but by the end of the Second Punic War in 202, Rome would have noticed a serious reduction in the number of iuniores aging into service. By 202 BCE, a combination of age, battle deaths, and low birth rate would have drastically reduced the iuniores population. The 15 year reduction in birth rates would have made that population shrinkage very long lasting. After rebounding somewhat to 214,000 in 203 BCE, as children born before the war came into adulthood, the number of Roman citizens plummeted to 144,000 in 193 BCE. Although census figures are certainly not entirely accurate, it is difficult not to blame declining birth rates for such a large peacetime drop in population.  

This graph shows birth rates of various European countries during World War One. I include it to give a general sense of how much birth rates drop during wars. I don’t want to suggest a direct comparison, given the immensely different social contexts, but bear in mind that WWI lasted four years, while the Second Punic War lasted sixteen.

Experts who study the effect of demography on international politics would say that a shortage of young men will lead to a country being more stable and less likely to get involved in wars. This theory, known as the ‘demographic peace’ model, helps explain why bloodier wars tend to have longer intervals between them when compared to smaller conflicts. Yet the Roman Republic did precisely the opposite of what the demographic peace model would suggest. The Roman army didn’t demobilize at the end of the Second Punic War. Instead, just two years later, the Romans sparked another major war by invading neighboring Macedon. For the next fifty years, Rome engaged in a series of expansionist conflicts across the Mediterranean, conquering large parts of modern-day Greece, Spain, Turkey, and North Africa.

Between 200 BCE and 146 BCE, Rome went from controlling Italy, Sicily, Sardinia, and Corsica to ruling all the area shown on the map. Such rapid expansion happened despite seriously a class of iuniores which by 193 was the smallest it had been in many decades.

The number of soldiers required for such an effort was immense. During the Roman war against the Seleucid Empire, between 192-188, the Roman Republic fielded 13 legions, or about 71,500 men. If the census can be believed, at the same time, Rome had only about 144,000 citizens, perhaps three quarters of whom would have been eligible for military service. 

2+2=5 (if you forget the poor people)

Something does not add up. How was Rome willing and able to maintain such enormous military forces, even as its traditional manpower pool shrank? The answer is surprisingly obvious, even if our sources do not fully admit it. During and after the Second Punic War, the Romans must have disregarded the wealth qualifications for military service. The proletarii, the Romans too poor to afford citizenship, were a large group which the census routinely undercounted. It is only through their widespread participation in the military that we can explain Rome’s ability to wage war on such a scale and for so long. 

Indeed, the census bears out this theory. In 193, just five years after listing 144,000 Romans, the population of Roman citizens leapt up to 258,000. The only explanation for such a rapid rise is a change in the way Rome counted citizens. It seems likely that Rome became more willing to give out citizenship, partly as a way to bolster its manpower, and also that Rome began to devote more effort to counting the proletarii, whose military service was finally vital to the state.

The sources do not mention the widespread recruitment of the poorer classes, but Polybius does suggest that the Romans did sometimes ignore property requirements. The Roman historian Livy, for his part, recounts the story of Spurius Ligustinus, a poor Roman who joined the legions in 200 BCE and served for 22 years, winning immense fame for his courage and skill. Livy mentions that Spurius Ligustinus did not meet the minimum criteria to enter into the legions, yet he gained entry nonetheless, despite the fact that the Second Punic War was by that point won. The existence of soldiers like Spurius Ligustinus points to a systematic bending of the property qualifications in the Roman army, even after the crisis of the Second Punic War was over.

The Roman military’s transition from a citizen army to a professional army drawn from the poor is perhaps the most important reason behind the creation of the Roman Empire. Recruiting the poor meant that men could stay in the legion indefinitely, rather than needing to return home to look after their land and property. At the same time, however, it meant that soldiers depended upon their generals for their livelihood, which would eventually cause armies to support the ambitions of their commanders over loyalty to the Republic. 

Traditionally, historians have argued that the Roman army began recruiting among Rome’s poor during the Marian reforms, around 105 BCE. More recently, it has become more popular to suggest that the transition began somewhat earlier. It seems to me, however, that given the demographic collapse of the iuniores population, the widespread military expansion of Rome during and after the Second Punic War, only makes sense if large numbers of poor Romans began serving in the legions much earlier than our sources suggest. 

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