marjaerwin

I went over the figures again, comparing info for slaves's rations as well as soldiers's rations. I don't know the appropriate price for olive oil, but I suspect that it was higher, and I suspect the slave population was even higher, than my last estimate.

(In case it wasn't clear, I think it is important to understand the size and structure of Roman slavery in order to study resistance to it.)

Roman Diet and Roman Slave Populations, 200 B.C.E. to 300 C.E.

Surviving Roman and Hellenistic sources suggest that agricultural slavery was strongly associated with certain industries, including wine and olive oil in the food industries, both cash crops, and wool in the clothing industry. Surviving Roman sources list rations for Roman slaves, and Jonathan Roth reconstructs rations for Roman soldiers, and surviving late Roman sources list the prices for Roman foods, which strongly suggest the relative labor requirements for growing and processing these foods.

Since the Roman Republic exported wine and imported grain, the relative labor requirements probably understate the relative number of slaves.

Since the Roman Republic was a pre-industrial society, the food industries were the largest part of the economy, and the proportion of slaves in the food industry, keeping in mind probably higher proportions of slaves in the clothing industries and certain other industries, should indicate the proportion of slaves in the entire economy.

Jonathan Roth's Reconstruction of Military Rations

Jonathan Roth offers the following reconstruction of the daily ration:

1. Grain 850 g/day 2 sextarii
or Bread 850 "
or Biscuit 650 "
2. Meat 160 1/2 libra
3. Vegetables 40-50 1/3 sextarius
4. Cheese 27 1 uncia
5. Olive Oil 40 1 1/2 unciae
6. Wine 160 1/2 sextarius
or Vinegar 160 1/2 sextarius
7. Salt 40 ?

Of course soldiers were not expected to support dependents out of these rations.

Ulrike Roth's Reconstruction of Slave Rations

Cato offers the following figures for the daily rations:

1. Wheat av. 900 g/day 3-5 modii per month, just over 1 1/2-2 1/2 sextarii per day
3. Vegetables ? sparingly
5. Olive Oil ? sparingly
6. Wine av. 160 1/2-1 1/2 sextarii per day
7. Salt ? 1 modius per year

Ulrike Roth suggests that the workers were expected to support dependents out of these rations.

Early and Late Imperial Prices for these Rations

Diocletianus's edict on maximum prices is the best available source for relative prices in the Roman Empire. It dates to the late Roman Empire, so we would have to adjust for hyperinflation to estimate nominal prices in the early Roman Empire or the late Roman Republic. For the ingredients listed above:

1. Grain 100 d/camp modius for wheat, and 6 d/camp modius for barley; assuming wheat
2. Meat 12 d/libra for pork, and 8 d/libra for beef; assuming beef
3. Vegetables 60 d/camp modius for beans and lentils
4. Cheese 8 d/libra for fresh cheese
5. Olive Oil 24 d/sextarius for ordinary olive oil
6. Wine 8 d/sextarius for ordinary wine
7. Salt 100 d/camp modius for salt (?)

1. Grain 850 g wheat 8.33 d/day, late 0.44-0.50 s/day, early Empire
2. Meat 160 g beef 4.00 d/day
3. Vegetables 40 g lentils 1.25 d/day
4. Cheese 27 g cheese 0.67 d/day
5. Olive Oil 40 g olive oil 3.00 d/day (?)
6. Wine 160 g wine 4.00 d/day
7. Salt 40 g salt 0.40 d/day (?)

A soldier's ration cost about 21.65 denarii/day in Diocletianus's time, or 1.21 sestertii/day in Augustus's time. Army records from Aegyptus from 81 C.E. suggest that soldiers had about 0.66 sestertii/day deducted to cover rations, which would be below cost. A slave's ration was probably cheaper, if it had less or no meat.

About 32% of the cost of the soldier's ration came from the wine and olive oil industries associated with slave labor. Given the similar amounts of wine in soldiers' rations and slaves', and the unknown amounts of olive oil in slaves', it is likely that these were typical diets for most Italians. And given that the Romans exported wine and imported grain and various other foods, it is likely that more than 32% of the Italian agricultural economy relied on slave labor and more than 32% of the Italian population were enslaved.

Major Sources

Robert Allen, "How Prosperous were the Romans?:
Evidence from Diocletian's Price Edict (AD 301)," 2009.
in Alan Bowman and Andrew Wilson, Quantifying the Roman Economy.
Peter Herz, "Finances and Costs of the Roman Army," 2011.
in Paul Erdkamp, A Companion to the Roman Army.
Dominic Rathbone, "Earnings and Costs: Living Standards and the Roman Economy
(First to Third Centuries AD)," 2009.
in Alan Bowman and Andrew Wilson, Quantifying the Roman Economy.
Jonathan Roth, The Logistics of the Roman Army at War, 1999.
Ulrike Roth, "The Female Slave in Roman Agriculture: Changing the Default," 2003.

So there are a lot of uncertainties about the events. Only fragments of Sallust’s histories survive, and that leaves much later sources from Plutarch’s lives and Appian’s histories, inter alia.

Appian mentions free rebels in one line. Diodorus mentions free rebels in three other uprisings, so it’s likely that there were some free rebels, but it’s unclear how many.

Sallust mentions Galli and Germani among the rebels. Plutarch also mentions Thraci. None of the sources mention Graeci or Asiaci, although recent Roman campaigns had enslaved tens of thousands of people in the East. None of the sources mention Italiaci, although most of the slaves in Roman Italia had grown up in Italia.

A better understanding of how many slaves there were in Roman Italia, and how many people, slave and free, joined the revolt, and what their backgrounds were, would be a good thing.