Numbers of troops in empires vs city states

[seleucid empire]

Ok so ive been thinking, if you look at the number of troops raised by large empires vs the number of troops raised by city states, theres this strange decrease in numbers as the empire gets bigger
for example: At marathon Athens, a single city state raised 10 000 hoplites for the battle. Athens controlled only Attica at the time
The Ptolemaic empire raised their largest army at Raphia and it had 70 000 men, The area of the Ptolemaic empire must have been 50 times the size of Attica
So my question is, why cant an empire 50 times larger raise 50 times the amount of troops? Is it due to corruption? Less loyalty from the subjects? harder to get the troops in one place?? what is it?

[Lysimachos]

1. An empire 50 times larger does not have 50 times the population, as most of its territory is covered by comparatively sparsely populated agrarian or barren areas. A city state has a much higher population density, which in turn means that in relation to its size it will always be able to field more troops than an empire.

2. The larger an army the harder it is to handle. Above certain numbers it makes less and less sense to enlarge an army.

3. The larger an empire the more places have to be guarded. If you can cross the whole domain in a short time, you can afford to concentrate everything at one place, but if you have to cross vast distances, you can't afford that.

4. The more dire the situation the more will a state be willing to exhaust its reserves to the last. Marathon was a matter of existence for Athens, much more so than Raphia for Ptolemy.

[Titus Marcellus Scato]

And:

5. The larger the empire, the lower the proportion of good quality fighting men relative to the population as a whole. In small states, wars involving the majority of the men fit and able to fight are more common. In large empires, there may be wars on the borders, but they are fewer and less common since enemies hesitate to attack such a large, strong empire, thus the people become more used to peace than war and become less warlike with time. Large empires have fewer soldiers and more farmers, tradesmen and slaves relative to population size.

Plus, in large empires, many of the men of fighting age may be of a different ethnicity and/or religion to the ruling class, and therefore the rulers may be reluctant to arm them in case they become rebellious and turn their weapons on their masters. Or they may simply be regarded as inferior racial stock, and thus not considered to be good quality fighting men. For example, the Seleucid and Ptolemaic empires tended to rely more on Hellenes as soldiers, and less on the native Iranians and Egyptians, who were far greater in number.

Finally, the cost of military and civil administration in a large empire becomes relatively greater the larger it becomes (bigger armies and empires are more difficult to keep organised), and thus there is relatively less wealth available to spend on the army. That's why there was a law of diminishing returns which naturally limited the maximum size of empires. The Roman army became very small relative to the empire's population size because the Romans simply couldn't afford to make it larger.

[seleucid empire]

Thats what im interested in, what causes the law of diminishing returns and how big is an empire before it kicks in

[rickinator9]

6. Unrest. Whereas Athens is only one people and culture(Greek) empires such as the Seleucid empire or the Ptolemies ruled several cultures. What happens when you rule several cultures? They all want their independence back and what better opportunity is there to rise up when the state is at war. Because of this, empires had to keep a garrison around at all times. For the city-state, what difficulty is there to keep one large city under control.

[Arjos]

The Ptolemaic empire raised their largest army at Raphia and it had 70 000 men, The area of the Ptolemaic empire must have been 50 times the size of Attica

Don't forget that at Raphia, Ptolemaios didn't call up his Makedonioi and Agema, they were left throughtout the empire to prevent uprisings...

Seleucid and Ptolemaic empires tended to rely more on Hellenes as soldiers, and less on the native Iranians and Egyptians, who were far greater in number.

Not true, not even one bit...
Both levied and trained locals in the macedonian fashion or employed semi-professionals with their own fighting style...

They considered the Makedonioi superior, but they were vital for the assemblies and needed to be preserved at all costs...

[Brennus]

Well I certainly learnt some new things today. Thanks everyone!

[Moros]

One may easily forget, especially in total war games, that the empire (speaking about the hellenistic ones) in this age didn't control the Poleis very much. It had only lose grip on it, unless shortly after a war. A polis chose as sometimes as much his king as a king chose which poleis to rule. That why we see kings buying off loyalty of poleis, (euergetism), giving them certain rights (for example not having to pay taxes* which is called aphorologetos or the right to make their own coins), gifts (for example a gymnasion). A polis usually also got aphrouretos or anepisthathmos which meant that they didn't need to have a royal garrison. Sure they paid war taxes and some troops, but obviously not as much as when the more ancient or independent polis itself was at war or at danger.

*Note there were many ways a king could get money out of a polis.

A great read that shows the relationships between Poleis and their basileus is: Antiochus III and the cities of western Asia Minor by John Ma (Oxford, 1999). (Almost anything of him is worth reading btw!)

[jirisys]

Also remembering the fact the hellenistic kingdoms sometimes got a influential man from the city to be part of the political and military body (philoxenia).

And the many links "were instrumental in the court’s policy of influencing the internal politics of cities"

And the "Xenoi of the Seleucid family who served as courtiers, commanders or ambassadors would normally retain links with their families and cities of origin, presumably through several generations. They often acted as mediators between the kings and their own communities of origin, deriving substantial benefits from both systems."

Political Culture in the Greek City After the Classical Age.
Chapter V: Kings and cities in the Hellenistic Age, Rolf Strootman.

~Jirisys ()

[Basileus_ton_Basileon]

They often acted as mediators between the kings and their own communities of origin, deriving substantial benefits from both systems."
~Jirisys ()

...In other words, they're sneaky little gits.

[Moros]

Also remembering the fact the hellenistic kingdoms sometimes got a influential man from the city to be part of the political and military body (philoxenia).

Of course. And those did bear influence, but those are were in part restricted to new founded (or refounded which could also mean reconquered) and royal settlements or recently conquered. They did their best to maintain loyalty from the city while keeping a most beneficial relation between king and state. But that still makes for a different situation. It's not because you accept to pay certain taxes or war taxes and send some troops, that you'll only put small part of your full military power at their service.

Poleis were very much aware of the fact that they were here to stay, contrary to the kings and kingdoms.