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

[Erpingham]

(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!)

I'm no expert on the Korean War but I'm not sure this is really compatable.  The Chinese deployed a smaller army over a much wider front and weren't tied to naval supply.

I am a bit baffled by the approach to modern analogy of the "source first" group.  Maurice has been rejected as he is too early 20th century British but Lawrence of Arabia has been cited with approval.  18th century practice is right out but the PVA in 1950 is OK.  Modern US and Pakistan army experience with mule transport is disregarded as too humane (as opposed to being based on operational requirements).

[Erpingham]

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.

Patrick is consistent in that he holds to the accuracy of Geoffrey of Monmouth's Arthurian tales, as we know from another thread.  He has even reconstructed the campaigns therein in some detail.  Needless to say, he found himself in (polite) conflict with those with an interest in Early Medieval Britain.   

[Justin Swanton]

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.

I checked the location of ancient Gonnus: it's just north of the Peneus on the other side of the pass - exactly where the Persians would arrive if they took the high ground north of the Tempe valley. This suggests that the Greeks thought the Persians would come along the valley floor and hence considered it an ideal blocking point as it is only a hundred yards wide. The Persians bypass the valley by going through "another pass leading into Thessaly by the hill country of Macedonia through the country of the Perrhaebi, near the town of Gonnus". They'll be coming down the slopes on a wide front, too much for the Greeks to handle.

[Flaminpig0]

(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!)

I'm no expert on the Korean War but I'm not sure this is really compatable.  The Chinese deployed a smaller army over a much wider front and weren't tied to naval supply.

I am a bit baffled by the approach to modern analogy of the "source first" group.  Maurice has been rejected as he is too early 20th century British but Lawrence of Arabia has been cited with approval.  18th century practice is right out but the PVA in 1950 is OK.  Modern US and Pakistan army experience with mule transport is disregarded as too humane (as opposed to being based on operational requirements).

There isn't a consistent  over arching methodology which is explainable -  we can disregard modern historians as they are 'not are not by training generals, economists, horsemen, merchants, seamen or waggoneers'. However, we can usefully draw on personal experience of C21 South African print shop operation or the experience of people watching Jefferson Airplane  or Tiny Tim at Woodstock. It is only a matter of time before  the well documented Dalek Invasion of Earth in 2150 is utilised in support of Herodotus.

[Erpingham]

It is only a matter of time before  the well documented Dalek Invasion of Earth in 2150 is utilised in support of Herodotus.

I know it is hard to resist a drift into sarcasm, but you must resist   I think there is value to the "sources first" challenge to the orthodox/conventional approach, in that it does avoid lazy thinking.  I've often come across an approach to ancient numbers in books where the an author just downsizes a figure by 10 without any rationale or a vague reference to Delbruck.  Patrick and Justin are right to shout "Oi, hang on a minute".  What I find difficult is, when criticisms of sources are deployed, they are picked at to expose issues, which are used to undermine the whole, or just ignored.  Also, if a range of critical opinions are raised, by disproving one you can wave the others away. 

I've confessed to be a fairly conventional thinker when it comes to history.  I was taught the value of the critical thinking at school and university and I'm pretty wedded to that paradigm.  I'm also wedded in numbers games to what I was taught in physics at school - does your answer look right when compared with other things you know?  So, in this case, if all other armies in Europe for which we have reliable figures in the pre-modern era are under 600,000 strong, is there a good case why this one should buck the trend?  Was there a technological advantage?  An organisational one?  Were the logistics especially simple?  Was the route more straightforward?  We don't seem to have evidence to answer yes to any of these questions - most of them come up no. 

[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.

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.

The point is that the army does not march through any narrow gaps that oblige it to contract to a column 8 men wide. It marches in a column or columns several hundred yards wide with the column(s) about 20 km long or so, which causes as much inconvenience as the columns of a regular army.

[Justin Swanton]

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?

The distance from Therma to the Haliacmon river is about 25km (15 miles).

[Erpingham]

The distance Therma to the Haliacmon river is about 25km (15 miles).

So, if we assume a fairly generous coastal strip of 1km, we have 25 sq km of concentration area.  We know Maurice would be thinking this small for an army of 210,000 men.  If it were one giant UNHCR camp, it would contain 833,000 people.  If it were all a big Roman camp, it could hold 2.5 million.  I think no-one would assume something the density of a Roman camp, not least because it assumes you can camp on every part of the available space, and we know it has watering points and the track several hundred yards wide running through it.  We obviously can't work out an actual number from this (because we don't really know how widely armies needed to be spread when concentrated to make for effective military operation, unless we take much later examples) but it would be a lot less than 3.5 million.

[Justin Swanton]

The distance Therma to the Haliacmon river is about 25km (15 miles).

So, if we assume a fairly generous coastal strip of 1km, we have 25 sq km of concentration area.  We know Maurice would be thinking this small for an army of 210,000 men.  If it were one giant UNHCR camp, it would contain 833,000 people.  If it were all a big Roman camp, it could hold 2.5 million.  I think no-one would assume something the density of a Roman camp, not least because it assumes you can camp on every part of the available space, and we know it has watering points and the track several hundred yards wide running through it.  We obviously can't work out an actual number from this (because we don't really know how widely armies needed to be spread when concentrated to make for effective military operation, unless we take much later examples) but it would be a lot less than 3.5 million.

No reason why we should assume a width of 1km. We can assume a width of 2km (half an hour to walk from the landward edge of the camp to the coast) and double the numbers. I walk 2km to and from work each day. It's nothing.

What is more difficult to assume is that an army of 150 000 to 200 000 men that camps in anything like Roman military concentration is going to need 25 - 30km of coastline

[Prufrock]

The point is that the army does not march through any narrow gaps that oblige it to contract to a column 8 men wide. It marches in a column or columns several hundred yards wide with the column(s) about 20 km long or so, which causes as much inconvenience as the columns of a regular army.

That's not what it means at all. It means that they didn't use the Tempe pass. It does not mean that they had a mountain superhighway over which they could march several million men in columns 200 men wide with neat spacing between ranks while also accommodating cavalry horses, pack animals and the supply train.

[Erpingham]

No reason why we should assume a width of 1km. We can assume a width of 2km (half an hour to walk from the landward edge of the camp to the coast) and double the numbers. I walk 2km to and from work each day. It's nothing.

A fairly broad strip but not impossible.  Something laid out on the density of a Roman camp I think would be stretching it though.

What is more difficult to assume is that an army of 150 000 to 200 000 men that camps in anything like Roman military concentration is going to need 25 - 30km of coastline

I think this goes back to what we have in our minds eye.  Maurice was envisaging a military concentration area.  A set of dispersed camps, each perhaps approaching Roman densities.  Or we might think in terms of one vast, organised but not strictly regimented camp a bit like a refugee camp.  These also tend not to be continous. 

Why it was so spread could be because there was no reason to tighten it up - the army was used to being spread over a march distance of a couple of days, maybe with the elite units at the front and the ones further back wading through a sea of detritus every day.  Or, as Herodotus seems to be thinking, access to water is the issue.  Doesn't really tell us a lot in absolute terms except the army was big and nobody disputes that.

[Justin Swanton]

The point is that the army does not march through any narrow gaps that oblige it to contract to a column 8 men wide. It marches in a column or columns several hundred yards wide with the column(s) about 20 km long or so, which causes as much inconvenience as the columns of a regular army.

That's not what it means at all. It means that they didn't use the Tempe pass. It does not mean that they had a mountain superhighway over which they could march several million men in columns 200 men wide with neat spacing between ranks while also accommodating cavalry horses, pack animals and the supply train.

I'm trying to form an idea of just how difficult the ground north of the pass is. Here's an image of a Drakensberg hike I did, from Giant's Castle hotel (red dot at bottom) to Bannerman's hut (red dot at top). The distance is 7km and took about 4 hours. It's what hiking books would term 'difficult'. Tiring but not really exhausting and not dangerous.



Here, on the same scale, is the hilly ground north of the river valley. Distance from the flat plain below to the summit ridge is about 4km; distance from the summit ridge to the plain beyond is about 3km. It's less steep than the Drakensberg climb. I'd say quite manageable for men and animals in a number of columns that avoid the steep bits. The traversable area looks to be about 1,5km wide.

[Justin Swanton]

No reason why we should assume a width of 1km. We can assume a width of 2km (half an hour to walk from the landward edge of the camp to the coast) and double the numbers. I walk 2km to and from work each day. It's nothing.

A fairly broad strip but not impossible.  Something laid out on the density of a Roman camp I think would be stretching it though.

What is more difficult to assume is that an army of 150 000 to 200 000 men that camps in anything like Roman military concentration is going to need 25 - 30km of coastline

I think this goes back to what we have in our minds eye.  Maurice was envisaging a military concentration area.  A set of dispersed camps, each perhaps approaching Roman densities.  Or we might think in terms of one vast, organised but not strictly regimented camp a bit like a refugee camp.  These also tend not to be continous. 

Why it was so spread could be because there was no reason to tighten it up - the army was used to being spread over a march distance of a couple of days, maybe with the elite units at the front and the ones further back wading through a sea of detritus every day.  Or, as Herodotus seems to be thinking, access to water is the issue.  Doesn't really tell us a lot in absolute terms except the army was big and nobody disputes that.

A good gauge for camp density would be contemporary squatter camps. The layout of a squatter camp is self-regulating and not governed by municipal laws, i.e. the people live as close together as possible whilst still having some sort of a life. Here's a typical example from Nairobi: 6000 people who live on 5-6 hectares. They have no electricity or running water and no sewerage system, but they manage to get by in a permanent setup with 2 water taps and 3 pit latrines.

Here's an extreme case: between 800 000 and 1 000 000 people live on 255 hectares, which means 1 person per 2,5m². Mortality here is high. I can't imagine the Persian camp being this packed.

A marching camp needn't worry as much about sewerage: holes dug in the ground are enough. 1000 people per hectare seems quite manageable if less than idyllic.

[Erpingham]

A good gauge for camp density would be contemporary squatter camps. The layout of a squatter camp is self-regulating and not governed by municipal laws, i.e. the people live as close together as possible whilst still having some sort of a life.

How the mighty have fallen.  We've gone from one of the most highly organised armies in pre-modern history to a migrating squatter camp of gigantic proportions.  Perhaps time for some reflection on the difference? I don't think the highly ordered supply and march routine and the mobile squatter camp are easy bedfellows.

[Justin Swanton]

A good gauge for camp density would be contemporary squatter camps. The layout of a squatter camp is self-regulating and not governed by municipal laws, i.e. the people live as close together as possible whilst still having some sort of a life.

How the mighty have fallen.  We've gone from one of the most highly organised armies in pre-modern history to a migrating squatter camp of gigantic proportions.  Perhaps time for some reflection on the difference? I don't think the highly ordered supply and march routine and the mobile squatter camp are easy bedfellows.

let me clarify. I've visited several squatter camps and they can be well organised, clean and tidy. The point is that their inhabitants must fit into as little space as possible whilst still maintaining living conditions and do it with a virtual absence of a modern infrastructure. They need to be able to perform all the functions of a human community without making life unbearable for themselves. With this in mind, 1000 people per hectare is workable for a permanent settlement. It is more than adequate for a temporary camp that lasts only a few days at the most.