The Marian reforms of the late Roman Republic changed Rome's military into a standing, professional volunteer force and greatly enhanced its effectiveness, thereby ensuring Rome's dominance for centuries to come. However it also came with significant social consequences, being a major cause of the Republic's transition into the Empire. This is due to the inclusion of landless masses into the military; previously only those who owned at least so much land could be conscripted, and by the late Republic the military suffered from severe manpower shortages.

My question is, what were the causes of those manpower shortages? Why were the eligibility requirements adequate for the early Republic and not during Marius's time? Marius's immediate motivation may have been that he was tasked to fight a war without men, but the problem was chronic - apparently the property limits were reduced from 11,000 to 3000 sesterces by Marius's time.

  • Did Rome suffer from a shortage of eligible landowning citizens, and if so why? Rising inequality?
  • Did Rome face a different strategic situation - e.g. more powerful enemies - and required a proportionally larger military?
  • Population and nutrition standards were falling, mainly due to climate. Also, the aristocracy had low fertility to preserve inheritances.
    – D J Sims
    Commented Sep 27, 2016 at 1:55
  • The social impetus was recognized by the Gracchi, who had Commented Sep 27, 2016 at 11:43
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    The social impetus had been recognized by the Gracchi, whose reforms had been supressed by the conservative aristocracy. Marius was the next stage of reform. His followers, the popularii, were passed on to Julius Caesar. Commented Sep 27, 2016 at 11:46

3 Answers 3


As the territorial extent of the republic grew, the citizens who were eligible for service in the military were seeing ever increasing terms of service. The vast majority of the citizenry who served as infantry in the republican militia were landowning farmers who, as a result of the growing extent of the republic, were seeing deployment to provinces such as Hispania, Asia or Syria.

The system of levy established during the early republic which depended on these citizen farmers would deploy for a single campaigning season, coinciding with the planting and harvesting of crops. As a result of the extension of length of service in further afield provinces the citizen farmers would no longer be able to return to their farmsteads in order to plant and harvest their crops and so their land fell into a state of neglect.

The senators of Rome were not permitted to engage in any mercantile activities to generate income and so the acquisition of land was a priority (however it must be noted they were not the only rich individuals engaged in such practices). The neglected farmsteads of the citizens soldiers serving in the provinces were acquired by the rich who would employ slave labour to maximise the profitability of the estates and subsequently these events and circumstances created a number of issues, two of which were:

  1. A severe lack of eligible citizen farmers for military service and;
  2. Mass unemployment for citizens

Plutarch notes in the Life of Tiberius Gracchus Ch.8:

Of the territory which the Romans won in war from their neighbours, a part they sold, and a part they made common land, and assigned it for occupation to the poor and indigent among the citizens, on payment of a small rent into the public treasury.

He goes on in greater detail about the causes of the symptoms you mention in your question which continued well into the first century B.C. which the Gracchi and others attempted to rectify with Julius Caesar being another.

And when the rich began to offer larger rents and drove out the poor, a law was enacted forbidding the holding by one person of more than five hundred acres of land. For a short time this enactment gave a check to the rapacity of the rich, and was of assistance to the poor, who remained in their places on the land which they had rented and occupied the allotment which each had held from the outset. But later on the neighbouring rich men, by means of fictitious personages, transferred these rentals to themselves, and finally held most of the land openly in their own names. Then the poor, who had been ejected from their land, no longer showed themselves eager for military service, and neglected the bringing up of children...

And as you have said, Marius capitalised on this and reduced the previously required property qualifications for service from property worth 3500 sesterces and having to supply his own arms to effectively no necessary qualifications. So the class known as the capite censi or "head count", i.e. those who had no property to qualify for being assessed in the the census, were now eligible for service in the military.

With the growth in territory naturally came an increase in bordering other states. One of the most notorious and organised of Rome's later rivals was the Parthians whom they often squabbled with over buffer states and border disputes as well as the migrating hordes of Gauls and Germans and rebellious, resistant Hispanic tribes. So yes, Rome did face a different strategic situation which required a greater level of organisation due to the increasing distance from Italy they engaged in conflicts and governance in.

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    So at least the beginning portion of your answer could be boiled down to the fact that a somewhat feudal-style levy-based army formed from landholding farmers was suitable for the early years of the Republic, when they were only needed/used for a single campaigning season, much as armies usually were in feudal times, but as the Republic grew ever larger and started transitioning into an Empire in that sense, they needed a larger and larger standing army, which the levies couldn't supply in the long term.
    – Rundil
    Commented Oct 24, 2016 at 11:04
  • @Rundil - Precisely. Reform was innevitable and imminent for a number of reasons, some of which were highlighted above. Commented Oct 24, 2016 at 17:43

The Roman Empire had lost 80,000 soldiers at the battle of Arausio, effectively destroying any remaining standing force in the Northern Empire. This was a hammer blow to the Aristocracy, many of who's warring generals were killed early on in the Cimbrian war.

Marius had three basic impetuses to initiate the landless:

1). From a wonderful source: The Social War of 91- 87 BCE (from the Latin socii allies) highlights that manpower was still a problem for the Roman army, as citizenship was granted to the allied Italians at the end of the war, granting a greater pool of men for the army.

2.) Adding on to the former point, the Aristocracy that was granted land in battle consisted initially of former plebeians. What this ended up doing was ensuring Marius had considerable power in terms of his command and loyalty from the Roman soldiers. This served to give him political influence and a tangible sign of power ("you and what army?...") over his rivals, such as the dictator Sulla.

3.) Yes, they did. Wikipedia's narration of the Cimbrian war states that the tribes almost always outnumbered the Romans by a margin not less than 7-8000 men. Roman styles of fighting in the trifold system they used had become ineffective due to superior numbers engaging multiple areas of the rank as well rather than allowing the periodical progression through the ranks as usually battles went with Republican Roman armies. Read more in my sources.

Hope this helped to a certain degree.

Sources: https://www.google.com/amp/s/www.ancient.eu/amp/1-11830/?client=safari https://en.m.wikipedia.org/wiki/Cimbrian_War Read here for more on the Reforms: http://romans.etrusia.co.uk/roman_army_print

  • I don't agree with the part about Sulla. He was never a semidictator but a full one twice, and only after Marius "bullied" him too much. If anyone was playing dirty politics at the time was Marius. The second point is also a bit confusing: if you fix it you'll get my vote, as the rest of your answer is good.
    – Brasidas
    Commented Sep 27, 2016 at 4:50
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    Good answer, but: you say that the social impact of the reforms was intentional, that Marius was seeking power from the landless. This contradicts wikipedia which says that he was "probably unaware of the momentous implications". Neither are sourced so I don't know what to believe. But the root of my question - why there were manpower shortages, enough to motivate the reforms - isn't really addressed here. Note that Rome lost a similarly large amount of soldiers during the Punic Wars, what was different this time? Commented Sep 27, 2016 at 5:53
  • Second point again, sorry :) As it reads now, the Marian reforms were aimed against "the dictator Sulla", but Sulla was not a dictator yet. And if that was Marius purpose, it sure backfired. Also, the "you and what army?" part is funny because Sulla marched on Rome with six legions and Marius had to flee. "Me and THIS army, you @#!!!"
    – Brasidas
    Commented Sep 27, 2016 at 19:00
  • @congusbongus I'm doing some more research and I'll update my answer again as soon as possible Commented Sep 27, 2016 at 23:20

This occurs as a country goes from "pre-Empire" to Empire. Another example was the Prussia of Scharnhorst and Gneisenau.

In the "pre-Empire" stage, a country needs a relative small, elite army, of which the aristocracy usually forms the core. This is used against a single, major enemy, e.g. Carthage. Here, quality is more important than quantity if your opponent is Hannibal.

After a country grows to a certain size, and becomes an "Empire," it develops "multiple" enemies, each of whom are smaller and weaker than itself. Here, the need is not for an elite army to beat one "high quality" enemy, but a "mass" army to beat down a number of enemies, each of which is small and weak by itself, but are numerous in the aggregate.

By about 100 BC, the time of the "Marian" reforms, Rome had made the above transition.

  • Some details in this answer seem inaccurate; the reforms improved Rome's armies both in quantity and quality, and by the Empire's time Roman strategy was usually to use a small, high quality force against weaker opponents, with exceptions like Parthia. The transition to low quality masses is during the late Empire's reliance on mercenaries. Commented Oct 26, 2016 at 1:45
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    I sort of understand what you're trying to say here, but one of the main reasons Rome did not capitulate during the Second Punic War was due to it's ability to raise new legions once Hannibal had destroyed existing legions. This negates your argument that Rome used quality over quantity when facing Hannibal. There are also other examples of Roman legions being heavily defeated but Rome itself was still capable of fresh levies to continue the wars. In fact, one of the Roman Republic's biggest attributes was it's ability to continually raise legions despite heavy losses. Commented Feb 1, 2018 at 19:45

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