Measuring the rate of cultural and social change

Posted by on March 13, 2008; This entry is filed under Uncategorized.
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Below I discussed the issue of whether the Roman Empire’s decline & fall was consequential. These sorts of discussions are loaded with presuppositions and impressions. Any one metric is not necessarily representative of other variables, and one must ask whether metrics are relevant in the first case. I think one important question to ask far upstream is this: does the rate of cultural change vary? In other words, does the first derivative of a cultural variable as a function of time deviate from zero? I think it does. For example, it seems that the period between 1950-1965 witnessed less change on average and in totality in the Zeitgeist than that between 1965-1970. In other words, someone in 1965 would recognize the general outlines of the society as less alien 15 years before than 5 years into the future.

With that assumption under the belt, the question we might ask about the Roman Empire is this: was there a discontinuity in the change so that one could say that the barbarian invasions were very significant? Or did the classical world of late antiquity slowly melt into the early medieval period. Most everyone can agree that production, material and intellectual, tended to decrease. But was the 6th century, for example, a period of particularly sharp decline in Italy? Traditional narrative history has a story to tell about the disruptive impact of the wars between the Goths and the East Roman Empire; that in the process of reconquering Italy Justinian destroyed it.

But enough. I have a copy of Contours of the World Economy 1-2030 AD, which has a handy chapter on the economy of the Roman Empire. Below the fold I’ve reformatted some of the population data to put it out on the web.

 Population in 000s

200 BC 1 AD 200 AD 400 AD 600 AD

Italy 5000 7000 7000 5000 3500

Iberia 4500 5000 5500 5000 4000

Roman Gaul 4400 5750 7500 5750 4500

Greece 2500 2000 2000 1500 800

Danubian lands 2550 3050 3550 3450 2600

Roman Europe 18950 22800 25550 20700 15400

Asia Minor 5000 6000 7000 6000 5000

Greater Syria 2600 3025 2750 2200 1900

Cyprus 200 200 200 200 200

Roman Asia 7800 9250 9950 8400 7100

Egypt 4000 4000 5000 4000 3000

Cyrenaica 300 400 500 300 200

Maghreb 2200 3800 4000 3600 3600

Roman Africa 6500 8200 9500 7900 6800

Total 33250 40250 45000 37000 29300

200 BC – 1 AD 1 AD – 200 AD 200 AD – 400 AD 400 AD – 600 AD

Italy 2000 0 -2000 -1500

Iberia 500 500 -500 -1000

Roman Gaul 1350 1750 -1750 -1250

Greece -500 0 -500 -700

Danubian lands 500 500 -100 -850

Roman Europe 3850 2750 -4850 -5300

Asia Minor 1000 1000 -1000 -1000

Greater Syria 425 -275 -550 -300

Cyprus 0 0 0 0

Roman Asia 1450 700 -1550 -1300

Egypt 0 1000 -1000 -1000

Cyrenaica 100 100 -200 -100

Maghreb 1600 200 -400 0

Roman Africa 1700 1300 -1600 -1100

Total 7000 4750 -8000 -7700

200 BC – 1 AD 1 AD – 200 AD 200 AD – 400 AD 400 AD – 600 AD

Italy 40.00% 0.00% -28.57% -30.00%

Iberia 11.11% 10.00% -9.09% -20.00%

Roman Gaul 30.68% 30.43% -23.33% -21.74%

Greece -20.00% 0.00% -25.00% -46.67%

Danubian lands 19.61% 16.39% -2.82% -24.64%

Roman Europe 20.32% 12.06% -18.98% -25.60%

Asia Minor 20.00% 16.67% -14.29% -16.67%

Greater Syria 16.35% -9.09% -20.00% -13.64%

Cyprus 0.00% 0.00% 0.00% 0.00%

Roman Asia 18.59% 7.57% -15.58% -15.48%

Egypt 0.00% 25.00% -20.00% -25.00%

Cyrenaica 33.33% 25.00% -40.00% -33.33%

Maghreb 72.73% 5.26% -10.00% 0.00%

Roman Africa 26.15% 15.85% -16.84% -13.92%

Total 21.05% 11.80% -17.78% -20.81%

A few thoughts? First, look at Greece. The Roman Empire wasn’t so hot for it, but remember that prior to the conquest of this region it was a major center of Hellenistic civilization under the Macedonians. Italy’s economic boom was in large part based on plunder, and Greece’s no longer (in fact, Greece was one of the major sources of high value slaves for Italy). Also, the data points hide a lot in between. During the mid-200s the Roman Empire nearly collapsed, and by 300 it had been resurrected by a series of reforms under the emperor Diocletian. So the difference between the year 200 and 400 likely masks that there might have been a minimum point sometime late in the 200s. Finally, you can see some regional dynamics. The recovery of the late 3rd century was under the aegis of emperors derived from the Danubian provinces, so the relative robustness between 200-400 can be attributed to the likelihood that the military and cultural outlays enabled by increased taxation benefited these regions via redistribution.

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11 Comments

  1. David Ross March 13th, 2008 at 9:56 pm

    I am finding it hard to tell the difference between Maghreb and Cyprus on this chart, due to similar coloration. I have to assume Cyprus is on the bottom and Maghreb in the middle. 
     
    Also, to nitpick, “Maghreb” is an anachronism for lands which saw few free Arabs until the mid 600s. (May as well call Asia Minor “Turkey”.) “Africa” was the Romans’ term for this region, but “Mauretania / Carthage” may work too. Anyway… 
     
    Africa-Minor followed Cyrene & Iberia in accelerating decline until 300 when the former one reached an inflexion point and the latter two… didn’t. Heather’s book taught me that Africa-Minor had become the breadbasket of the western Roman world as of 400, so we’re probably seeing an echo of the shift of the western Roman economy. 
     
    Africa-Minor’s population-increase post 400 AD surprises me, because supposedly a horde of Vandals took over in the 400s and laid waste to generations of careful husbandry and irrigation. These Vandals beat Emperor Leo in the 400s and folded like a deck of cards to Justinian in the 500s, and in the 600s the Arabs’ main adversaries there were Berber guerrillas (hinting at deurbanisation, particularly deRomanisation). Why isn’t the population dropping like the proverbial stone? 
     
    Greater Syria’s relative demographics at the time of Zenobia’s rebellion (mid 200s) illustrates eloquently why that rebellion was a folly. But then, it probably looked like a good idea at the time.

  2. Sandgroper March 13th, 2008 at 11:23 pm

    Correct. To my eyes, the colours are not similar at all.

  3. razib March 14th, 2008 at 12:08 am

    david, surprised me too. though we need to take some of these data with a grain of salt. cyprus obviously didn’t have large enough data sets where you could deviate from the 200,000 number that maddison has invariant acros this time period.

  4. michael vassar March 14th, 2008 at 5:59 am

    Do we have good sources for the numbers?

  5. Shorty March 14th, 2008 at 9:42 am

    Do the population estimates include slaves? 
    In this case the “reproducing” population is overestimated in some areas in the first century or so, especially in Italy. 
    I suspect survival among slaves was probably very close to zero. 
    In those cases the real figure could be lower by 10%. I am guessing of course. 
    That would probably make the use of the figures almost uselss for some regions. It wold make Italy’s curve much flatter.

  6. Judith Weingarten March 14th, 2008 at 10:16 am

    I’m a little puzzled by the figures from Syria. I know of nothing that would have caused a population decrease before ca. 200 AD. On the contrary, until the Sassanian invasions after mid-third-century, it was a relatively flourishing province. To bang on about money again, the silver content of coins minted in Antioch was higher than in the west. And Antioch was the second (or third, depending on who was boasting) city in size in the whole empire. And continued as such for a long while yet.  
     
    Whereas, in the 200-400 period, eastern Anatolia suffered as much as Syria from the Persians, PLUS devastation in the north and west from Goths. Yet their population doesn’t drop as much!?!  
     
    I think one needs a better look at the sources. Certainly, before writing off Zenobia’s good judgment :-)

  7. razib March 14th, 2008 at 12:19 pm

    In those cases the real figure could be lower by 10%. I am guessing of course. 
     
    well, yeah, but effective population is 1/3 of total for rule of thumb if you want to rescale it that way. 
     
    maddison obviously didn’t make it up, but i can’t really succinctly explain his sources or rationales. i would suggest the ‘search inside’ feature on amazon. google for these pop data.

  8. Shorty March 14th, 2008 at 5:36 pm

    If the graph includes the slave population then the drop in population that occured in some areas was lower and they give a distorted perception. Slavery probably lost its appeal and was mostly abolished after. 
    This also means that up until the more massive foreign invasions and raids of every type and creed in many areas life continued with little change except maybe that it became more rural. 
    Perhaps the fall of the western empire per se was not so traumatic for the common folk, but it deprived the region of a common defence system and that was the real problem. 
    Personally, I find that graphs (or studies) like this are very imprecise if they do not consider what should be obvious.

  9. razib March 14th, 2008 at 7:25 pm

    shorty, don’t talk out your ass, OK? i’m not interested in your personal opinions based on nothing. mostly “abolished”? jesus.

  10. toto March 15th, 2008 at 5:30 am

    does the rate of cultural change vary? In other words, does the first second derivative of a cultural variable as a function of time deviate from zero? 
     
    FTFY. (I like the smell of pedantic nitpicking in the early afternoon…)

  11. razib March 15th, 2008 at 11:49 am

    tx toto ;-)

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