Celts - do you find it Gauling how rulesets treat them...

[Justin Swanton]

On the very rough basis of 1kg of cereals a day, that 1000-1500 person days.  For Roy's 250,000 strong army over 40 days, you'd need 6700-10000 carts.  Given they are advancing from many directions, they may be able to cut enough fodder as they march (with the usual caveats of time cost).  It is possible, using arrangements with tribes en route to provide some supplies, this number could be reduced.  Again, this is "order of magnitude" stuff, not an accurate assessment.

I understand this wasn't the point of the post... but please forgive some satire.
10,000 carts Parkes arse to nose, would single file, be about 80km of baggage, and the troops would eat 12% of the supplies before the rear cart got to the front. God knows what the baggage animals would eat of the carts contents...

I remember us covering this in the Achaemenid thread. 10,000 carts don't all advance together in single file. They are divided up between different tribes and different contingents of those tribes and the wagons of a single contingent don't necessarily all travel in single file. I suspect we often have Napoleonic corps in mind when visualising an army travelling cross-country on a single road, but keep in mind that Napoleon split his army into corps precisely so they wouldn't travel together.

[Dangun]

Maybe the economic cost of logistics in the classical period is so high, that logistics is the under appreciated economic incentive for a professional soldiery?

As the cost of logistics rises, it will make increasing sense to invest in skills instead.

[Dangun]

I remember us covering this in the Achaemenid thread. 10,000 carts don't all advance together in single file. They are divided up between different tribes and different contingents of those tribes and the wagons of a single contingent don't necessarily all travel in single file. I suspect we often have Napoleonic corps in mind when visualising an army travelling cross-country on a single road, but keep in mind that Napoleon split his army into corps precisely so they wouldn't travel together.

All true.
But the big-number advocates don't seem to worry very much about that at a certain size, its just a logical necessity an army will spend its entire time walking into and out of the camp for water.

[Justin Swanton]

I remember us covering this in the Achaemenid thread. 10,000 carts don't all advance together in single file. They are divided up between different tribes and different contingents of those tribes and the wagons of a single contingent don't necessarily all travel in single file. I suspect we often have Napoleonic corps in mind when visualising an army travelling cross-country on a single road, but keep in mind that Napoleon split his army into corps precisely so they wouldn't travel together.

All true.
But the big-number advocates don't seem to worry very much about that at a certain size, its just a logical necessity an army will spend its entire time walking into and out of the camp for water.

Not if you camp along the length of a river (also looked at in the Achaemenid thread).

[Dangun]

Not if you camp along the length of a river (also looked at in the Achaemenid thread).

I remember, and t=hat doesn't change anything either.

Quite apart from the fact that your movement or even existence in a single location is limited by the driest step along the route...
Pick whatever shaped water source you like, maybe a Pacific Ocean full of fresh water. There is still a maximum size because an army still has to move to water and back and still allow time in the day for something useful like movement.

[Justin Swanton]

Not if you camp along the length of a river (also looked at in the Achaemenid thread).

I remember, and t=hat doesn't change anything either.

Quite apart from the fact that your movement or even existence in a single location is limited by the driest step along the route...
Pick whatever shaped water source you like, maybe a Pacific Ocean full of fresh water. There is still a maximum size because an army still has to move to water and back and still allow time in the day for something useful like movement.

I remember us working out how many bodies one can reasonably cram into a km² and then calculating the dimensions of a camp for 5 million Persians along each reasonably-size river between the Hellespont and Thermopylae they would need to stop at and, IIRC, nobody would have to walk more than half an hour to reach water. For 250,000 Gauls it really shouldn't be a problem (and there are plenty of rivers in Gaul).

[Erpingham]

Justin is perhaps remembering the Persian thread differently to me, but the failure to understand the nature of watering operations led to flights on fancy on the parts of some.  Also a huge preparatory army had to strip vast areas and make fodder dumps in advance of the army.  One thing that doomed the idea of a large army was the shear logistic impossibility of it.  But this proposed army is much smaller, it is not limited to a single axis of approach.  So, there are a number of differences.

[Justin Swanton]

But this proposed army is much smaller, it is not limited to a single axis of approach.  So, there are a number of differences.

True. You are probably looking at contingents that individually don't number above the low tens of thousands, so water shouldn't be a problem (however one looks at the Achaemenids  )

[Imperial Dave]

Vercingetorix

you lot, you lot and you lot, meet me at such and such and bring lots of food and clobber for a shin-dig with the Romans in 2 weeks time

[Justin Swanton]

Vercingetorix

you lot, you lot and you lot, meet me at such and such and bring lots of food and clobber for a shin-dig with the Romans in 2 weeks time

And we do need to keep in mind the Gallic appetite...

[Imperial Dave]

nearer reality than previously given credit for I suspect