Tuesday, April 9, 2019

4,450 Seleucid coins from the Bibliothèque nationale de France added to SCO

This morning I received a new spreadsheet from Julien Olivier of the Bibliothèque nationale de France with approximately 6,500 coins connected to URIs defined in PELLA and Seleucid Coins Online. Some 2,000 Alexanders from the BnF have been incorporated in PELLA for quite some time, but we are happy to announce this latest export includes 4,450 coins from the Seleucid Empire. This nearly doubles the number of specimens available in SCO. The ANS has contributed about 4,800 itself. There are now nearly 9,700 physical coins linked to about 2,500 parent types in SCO.

Furthermore, all of the coins from the BnF are photographed and high resolution imagery is available through the IIIF protocol.

SC 379 (Antiochus I tetradrachm) is one of the best represented specimens.

Tuesday, April 2, 2019

D3js-based Charts Migrated to Production

Although I am still working on ironing out some issues with full internationalization of the interface and SVG/image downloads of charts, the new interface has been pushed into the production installation of Numishare, so these new features are now available in OCRE, CRRO, and the Hellenistic Royal Coinages projects. I have yet to create a forwarding mechanism that will parse request parameters for the first iteration of the metrical analysis interface and generate a new series of parameters for the current one. I should have that functioning by the end of the week.

Comparing weights of denarii and antoniniani over three centuries.

The chart above (linkable here) illustrates the change in average weight of denarii and the introduction and evolution of the antoninianus from 30 B.C. to A.D. 300. The antoninianus, introduced by Caracalla in 215, was intended to be valued as twice that of the silver denarius, but as we can see from the wealth of measurement data we have (42,702 weighed specimens connected to RIC types within this date range [see https://gist.github.com/ewg118/b1989d1604da6c14964217bea96c142b for the SPARQL query]), the average weight of antoniniani minted in 215-220 is 4.88g, which is only 59% heavier than the denarii minted during the same period.

So already, the Roman Empire is cutting corners economically by issuing "double" valued currency with lower levels of weight/silver content. Citizens would have been better off hoarding denarii.

In the next five-year span, the weight of antoniniani goes up a bit while the denarii go down, resulting in a roughly 1.7:1 ratio, but denarii are still prominent in production, comprising 42% of all denominations minted during this period, compared to about 3% for antoniniani (http://numismatics.org/ocre/visualize?type=percentage&category=denomination_facet&compare=year_num%3A%5B220+TO+225%5D).

After 240, by the time we reach the beginning of the Crisis of the Third Century, the average weight of the antoninianus declines precipitously until it hits rock bottom from about 265 to 275, when it barely weighs above (or even below, briefly) the denarius. At this point, production of silver coinage in the Roman Empire transitions almost exclusively to the antoninianus, 64% to 6% for denarius and quinarius (the remaining 30% being bronze or gold [see data here]).

Distribution of denominations produced 260-274.

The denominations begin to increase in weight and value beginning in 275 as the Roman Empire begins to emerge from its three decades of internal strife and hyperinflation, though the antoninianus will never come close to recovering its intended 2x value.

These, of course, are facts we already knew through intensive study of the Roman economy. But we have a wide variety of typological and metrical data available, enabling us to generate visualizations and downloadable CSV (that can be integrated into other statistical/data science platforms) much faster than ever before. If our data tell us what we already know, then we can be confident that new research questions developed upon these data will yield accurate results.