Could the Persian Empire logistically support an army several million strong?

[Patrick Waterson]

AS an alternative comparator, what if we look at the Persian camp as more like a refugee camp - a few functional areas like hospitals, storage, assembly spaces and some closely arranged tents? If we take UNHCR guidelines

The average camp size is recommended by UNHCR to be 45 sqm per person of accessible camp area.    Sleeping accommodations are frequently tents, prefabricated huts, or dwellings constructed of locally available materials. UNHCR recommends a minimum of 3.5 sqm of covered living area per person. There should be at least 2m between shelters. 

The UNHCR allow 15sq m garden space per person, so actual camp density would be at 30 sq m per person.  In real lfe, they can be denser but lets stick to the guidance.  Of course, UNHCR camps tend to be settled with some infrastructure, so may well be more sophisticated than a daily camp.  But then again, they don't have thousands of cavalry and baggage animals. 

Interesting approach, and we can probably contract it some more by assuming the Achaemenids, like other armies, are not too picky about assigning 10'x10' to the average soldier.  If however we stay at 30m per person overall this gives about 333 people per hectare, quite a bit denser than US training camps and significantly more so than Maurice's concentration areas.

Getting back to animal logistics, I am left wondering what proportion of the baggage train consisted of camels.  In some ways, camels are a logistician's dream: their supply requirement is not necessarily less than that of other animals, but they have the ability to defer it, or more accurately carry much of it with them in that thing known as a hump.

In practice, this means Xerxes' army would not have had to carry fodder for its camels, because they would replenish themselves at the next grazing area.  They are also quite tolerant of going the odd day or two without water, which may be why the rivers which did not suffice for the entire army did not result in massive animal mortality: watering the camels only once other requirements were satisfied would make good use of these animals' ability to sustain themselves from internal resources (they could replenish at the next adequate water source) and give some flexibility in water management.

A thought about pasturage.

Judging by the number of Thracians Herodotus records as joining Xerxes' army (c.300.000) there would have to be significant pasturage areas to sustain their livestock.  Does anyone have any idea how many animals 300,000 adult male Thracians plus the population of northern Greece would maintain?  I do not, but suspect it would be quite a few, with concomitant grazing facilities.  And there is a kind of cruel logic to the Achamenid army's progress: as its baggage animals crop the grazing lands, consuming in a day or so what would perhaps have lasted the local livestock weeks (allowing for regrowth of grass), so the original livestock gets enlisted as part of the meat on the hoof contingent to replace its late predecessors in this role.

The Achaemenid invasion was timed to coincide with the spring grass; this would presumably remove much if not all of the need for fodder, assuming the continued survival of the bulk of the local livestock was not a major concern.  This would bring us back to a pack train which carries food for the men but not the animals, greatly reducing the requirement.  (Personally, I suspect a certain amount of stored fodder would anyway have been laid up as insurance, and also that the Achaemenids would empty the barns of areas they passed through if the grazing was not up to expectations.)

It may be unrealistic to assume that pasturage would be exactly where the army wanted it every day of the marching week.  It would not however be beyond the capabilities of the army's camp followers plus cooperative locals to cut plenty of fresh material and ensure it reached the campsite on time.

Poor chap, if he's been writing BC, we'd not bat an eyelid at his numbers.

But then, if he had been writing BC, would he have had the same numbers?

You aren't seriously suggesting that questioning Herodotus is racist?

Not the act of questioning itself (heaven forbid!) but the blinkered culturally-led way it seems to be done.

[Edited typo: 'wated' to 'wanted']

[Patrick Waterson]

The Achaemenid army ... animals ... are not expected to last.

That may be one of the key issues, not just for this expedition but for ancient logistics in general. Maurice, Engels and the like calculate consumption based on what's needed to keep pack animals in a usable condition; the picture is a bit different if they are expendable.

But are they expendable? If you're on a march for a limited time and you expect to be able to get new mules (camels, whatever) the next time you need them, yes. If you're still going to need the animals to shuttle food from shipborne deliveries to the army in six months' time, and your army's so big that Greece (which doesn't breed camels, or apparently all that many mules) can't supply enough replacement beasts, then your pack animals surely do need to last.

The question here would seem to be whether if the animals are operating on a one-week loading cycle (i.e. about 1/7 of their load is offloaded for consumption daily), one can start the week with an overload and finish it with an underload without harming the animals and sustain this over an indefinite period.

One feature of animal load manuals seems to be that they assume the animal will be carrying the same load on a continuing basis, i.e. it will have that load all the time.  But if the load starts heavy and then becomes progressively lighter over the next six days, is the animal better able to maintain its health and efficiency?  A mule loaded to 500 lbs at the start of such a week will be carrying nothing or a few empty containers by the end of the week and will on average be carrying the manual-stipulated 250 lbs.

[Justin Swanton]

I suspect that you are using a different approach to maurice.  He is thinking in terms of the sorts of concentration areas armies need to work from a fixed supply point and maintain military efficiency, not just how many men can be crammed in a space.  Doesn't mean he isn't on the generous side but lets try and get where he is coming from.  Poor chap, if he's been writing BC, we'd not bat an eyelid at his numbers .

AS an alternative comparator, what if we look at the Persian camp as more like a refugee camp - a few functional areas like hospitals, storage, assembly spaces and some closely arranged tents? If we take UNHCR guidelines

The average camp size is recommended by UNHCR to be 45 sqm per person of accessible camp area.    Sleeping accommodations are frequently tents, prefabricated huts, or dwellings constructed of locally available materials. UNHCR recommends a minimum of 3.5 sqm of covered living area per person. There should be at least 2m between shelters. 

The UNHCR allow 15sq m garden space per person, so actual camp density would be at 30 sq m per person.  In real lfe, they can be denser but lets stick to the guidance.  Of course, UNHCR camps tend to be settled with some infrastructure, so may well be more sophisticated than a daily camp.  But then again, they don't have thousands of cavalry and baggage animals.

I suspect that Roman army camping arrangements are our best comparative marker. The contubernum tent measured a little under 3 x 3m and could sleep 6 men at any one time (the other two were on guard duty).  Add a couple of metres between one tent and the next (as per UNHCR) and you have an area of 5 x 5m per tent which is per 8 men. So each man gets 3m². If you exclude space for kitchens, parade ground, latrines, officers' more luxurious accommodation and of course a corral for the animals, you get 3333 men per hectare. Cut that by 2/3 to include the extras but don't add space for camp walls or ditches and you come out at 1111 men per hectare. With this ball park figure 3 400 000 men will occupy 3060 hectares or 5,5 x 5,5 km. Xerxes would have wanted his camp as closely packed as possible so this figure seems to make sense. Pack animals could be spread out more thinly on the periphery of the camp the facilitate grazing. Overcrowding and its concomitant sanitary problems is not really an issue since the army will break camp the next day and move one.

[Flaminpig0]

You aren't seriously suggesting that questioning Herodotus is racist?

Not the act of questioning itself (heaven forbid!) but the blinkered culturally-led way it seems to be done.

[Edited typo: 'wated' to 'wanted']

So in essence yes

[Flaminpig0]

It would probably need to be over the hilly ground north of the Tempe valley which itself is a steep and narrow gorge. The army must be able to march in a column/columns several hundred yards wide at all times.

Sorry Justin I might be misunderstanding you but did you not in an earlier post say that it would be impossible for an army of 3 million to move along a single track?

[Justin Swanton]

It would probably need to be over the hilly ground north of the Tempe valley which itself is a steep and narrow gorge. The army must be able to march in a column/columns several hundred yards wide at all times.

Sorry Justin I might be misunderstanding you but did you not in an earlier post say that it would be impossible for an army of 3 million to move along a single track?

Sure Ian. The army obviously cannot march in the Tempe valley itself as it is too narrow, but the hilly ground just to the north of it is wide enough and not too steeply-sloping. Wouldn't be much fun though.

Should the army at any time be obliged to march through a narrow area that will stop it dead in its tracks. Suppose it marches 8 wide. The column would be 3 400 000 divided by 8 x 2 yards = 825km long. It would take a month to pass a given point.

[Prufrock]

Sure Ian. The army obviously cannot march in the Tempe valley itself as it is too narrow, but the hilly ground just to the north of it is wide enough and not too steeply-sloping. Wouldn't be much fun though.

Should the army at any time be obliged to march through a narrow area that will stop it dead in its tracks. Suppose it marches 8 wide. The column would be 3 400 000 divided by 8 x 2 yards = 825km long. It would take a month to pass a given point.

Not sure how practical it would be to march a couple of million men and beasts over these hills in a column several hundred men wide!

https://www.google.co.za/maps/@39.8817216,22.5921391,3a,75y,315.76h,104.63t/data=!3m6!1e1!3m4!1s7LfT-a1iXqED6zGWXNVj4A!2e0!7i13312!8i6656?hl=en

https://www.google.co.za/maps/@39.8585485,22.5315659,3a,75y,4.18h,110.33t/data=!3m6!1e1!3m4!1sXtDfxD6V6Q07VoouzopPAQ!2e0!7i13312!8i6656?hl=en

[Flaminpig0]

It would probably need to be over the hilly ground north of the Tempe valley which itself is a steep and narrow gorge. The army must be able to march in a column/columns several hundred yards wide at all times.

Sorry Justin I might be misunderstanding you but did you not in an earlier post say that it would be impossible for an army of 3 million to move along a single track?

Sure Ian. The army obviously cannot march in the Tempe valley itself as it is too narrow, but the hilly ground just to the north of it is wide enough and not too steeply-sloping. Wouldn't be much fun though.

Should the army at any time be obliged to march through a narrow area that will stop it dead in its tracks. Suppose it marches 8 wide. The column would be 3 400 000 divided by 8 x 2 yards = 825km long. It would take a month to pass a given point.

During this month the column would be being fed by supplies brought in by boat?

I am also wondering about how much excrement, dead bodies and other detritus would be piling up in such a comparatively small area - I suspect that by the end of the first week  the place would be a major health hazard.

[Justin Swanton]

Sure Ian. The army obviously cannot march in the Tempe valley itself as it is too narrow, but the hilly ground just to the north of it is wide enough and not too steeply-sloping. Wouldn't be much fun though.

Should the army at any time be obliged to march through a narrow area that will stop it dead in its tracks. Suppose it marches 8 wide. The column would be 3 400 000 divided by 8 x 2 yards = 825km long. It would take a month to pass a given point.

Not sure how practical it would be to march a couple of million men and beasts over these hills in a column several hundred men wide!

https://www.google.co.za/maps/@39.8817216,22.5921391,3a,75y,315.76h,104.63t/data=!3m6!1e1!3m4!1s7LfT-a1iXqED6zGWXNVj4A!2e0!7i13312!8i6656?hl=en

https://www.google.co.za/maps/@39.8585485,22.5315659,3a,75y,4.18h,110.33t/data=!3m6!1e1!3m4!1sXtDfxD6V6Q07VoouzopPAQ!2e0!7i13312!8i6656?hl=en

That's through the gorge.

This is the route I suggest: Starting here (gorge to the left), then a close-up, then here, then to the top, then shift right then (180 degree rotation of view) head down the slope, and further down to the widening valley floor, and there you are.

[Erpingham]

I suspect that Roman army camping arrangements are our best comparative marker.

This document on the Hyginus ideal camp and this study may be useful.  These provide a density of about 1160 per hectare for Hyginus, though the marching camp paper suggests 900-1000 per hectare may be more likely.

We should note Hyginus' army is under 50,000 strong, so we don't know from this how the Roman army would tackle encamping several million people.  I suspect given an army across the Empire about half a million strong, the question wouldn't have occured.  From the larger armies recorded of up to 200,000 strong, I don't know whether they used one mega-camp or a concentration area model as Maurice describes.

[Prufrock]

H 7.173 has the army go through Northern Macedon, Perrabia and come out near Gonnoi, so perhaps we are back with Young again in any case.

H does also mention in 7.131 using a third of the army to clear 'the Macedonian mountain' and create path for the army to pass through to reach the Perraibians.

[Prufrock]

I suspect that Roman army camping arrangements are our best comparative marker.

This document on the Hyginus ideal camp and this study may be useful.  These provide a density of about 1160 per hectare for Hyginus, though the marching camp paper suggests 900-1000 per hectare may be more likely.

We should note Hyginus' army is under 50,000 strong, so we don't know from this how the Roman army would tackle encamping several million people.  I suspect given an army across the Empire about half a million strong, the question wouldn't have occured.  From the larger armies recorded of up to 200,000 strong, I don't know whether they used one mega-camp or a concentration area model as Maurice describes.

We have Pompey at Dyrrachium, which is about the same density as Maurice gives for his Brits in France.

[Patrick Waterson]

Here is Xerxes' army encamped (Herodotus VII.127):

"When he had arrived at Therma, Xerxes quartered his army there. Its encampment by the sea covered all the space from Therma and the Mygdonian country to the rivers Lydias and Haliacmon, which unite their waters in one stream and so make the border between the Bottiaean and the Macedonian territory. In this place the foreigners [barbaroi] lay encamped; of the rivers just mentioned [in VII.124-126], the Cheidorus, which flows from the Crestonaean country, was the only one which could not suffice for the army's drinking but was completely drained by it."

Can we get an approximate size from this description?

Sure Ian. The army obviously cannot march in the Tempe valley itself as it is too narrow, but the hilly ground just to the north of it is wide enough and not too steeply-sloping. Wouldn't be much fun though.

Might be worth observing how many of the Persian contingents came from hilly or mountainous regions.  They would not have been too bothered about using hill tracks or just climbing hills or the odd mountain once in a while; even the Immortals managed Ephialtes' goat-track at Thermpoylae without problems.  I think we tend to be a bit too 'road-bound' in our thinking, like the US Army in Korea in 1950-51.  (Students of that conflict will recall the communist Chinese managed to move massive armies around in mountainous areas and keep them supplied, albeit not by Achaemenid methods!)

[Patrick Waterson]

You aren't seriously suggesting that questioning Herodotus is racist?

Not the act of questioning itself (heaven forbid!) but the blinkered culturally-led way it seems to be done.

So in essence yes

No, just the way it is done.

We grow up in our culture, with our culture's perceptions, which is well and good, for it enables us to survive, and on occasion prosper, in our culture.  This has the side-effect that we tend to see everything through the eyes of our culture, which is good up to a point, as it allows mutual understanding with those who have the same mindset.  But when dealing with history, we seem all too often to feel a compulsion to convert recorded historical events to conform with our own mindset, particularly when it involves some outstanding deed or performance.  There seems to be a compulsion to reduce such events to a squalid mediocrity, and for what reason or purpose?

This Procrustean process seems often to be disguised, or excused, under the pretext of applying a critical faculty.  There is nothing wrong with applying one's critical faculty to history, but much wrong with arbitrarily rewriting history to accord with the norms of one's culture under the pretense that one is employing one's critical faculty.  That is my gripe.

[If this develops into a philosophy-of-history discussion we might take it to a new thread.]

[Flaminpig0]

You aren't seriously suggesting that questioning Herodotus is racist?

Not the act of questioning itself (heaven forbid!) but the blinkered culturally-led way it seems to be done.

So in essence yes

No, just the way it is done.

We grow up in our culture, with our culture's perceptions, which is well and good, for it enables us to survive, and on occasion prosper, in our culture.  This has the side-effect that we tend to see everything through the eyes of our culture, which is good up to a point, as it allows mutual understanding with those who have the same mindset.  But when dealing with history, we seem all too often to feel a compulsion to convert recorded historical events to conform with our own mindset, particularly when it involves some outstanding deed or performance.  There seems to be a compulsion to reduce such events to a squalid mediocrity, and for what reason or purpose?

This Procrustean process seems often to be disguised, or excused, under the pretext of applying a critical faculty.  There is nothing wrong with applying one's critical faculty to history, but much wrong with arbitrarily rewriting history to accord with the norms of one's culture under the pretense that one is employing one's critical faculty.  That is my gripe.

[If this develops into a philosophy-of-history discussion we might take it to a new thread.]

Ooh, for once in my life I feel i am being  out-post-modernised

I would be interested to see how your approach to history works on analysing Geoffrey of Monmouth's The History of the Kings of Britain.