CURRENCY IN THE AGE OF DIOCLETIAN AND CONSTANTINE

In 215 Caracalla introduced an antoninianus or double denarius minted at 64 to the Roman pound (5.10 grs.) and only 52% fine so that it contained 80% of the silver of two denarii. Debasements in 238-270 reduced the antoninianus to a billon piece minted at 124 to Roman pound (2.6 grs.) and 2% fine. The ensuing inflation ruined imperial currency and price stability that had endured for three centuries. Aurelian in 274 and Diocletian in 293-296 reformed imperial money based on a billon coin, the nummus, which was tariffed in notational denarii communes ("common denarii" or d.c.).

Diocletian fixed the standard of the aureus, the principal gold coin, at 60 to the Roman pound (5.34 grs.) struck from almost pure gold (99-99.5% fine). An equally pure silver argenteus was struck at 96 to the pound and exchanged at 24 to the aureus so that each argenteus represented a carat (siliqua) or the equivalent weight of 1/24 of the aureus. The principal coin for daily transactions was a silver-clad nummus, struck at 32 to the pound (11.00 grs.) and coated with silver wash so that it was 5% fine. The nummus was tariffed at 5 d.c. in 293, but inflation forced Diocletian to revalue his currency twice, in 300 and again in 301, so that imperial currency was officially tariffed in in 293-307 as follows:

OFFICIAL VALUES OF IMPERIAL MONEY, 293-307 A.D.

Exchange Value

Denomination 293-300 300-301 301-307

Gold Aureus 600 d.c. 1,200.0 d.c. 2,400 d.c.

Silver Argenteus 25 d.c.   50.0 d.c.   100 d.c

Billon Nummus 5 d.c.   12.5 d.c.    25 d.c.

Billon Radiate 2 d.c.    2.5 d.c.    5 d.c.

Bronze Laureate 1 d.c.   1.0 d.c.    1 d.c.

Within eight years official values of imperial money were inflated by five times, but prices and wages cited in units of account or "ghost currencies" of d.c. are deceptive, because the number of nummi officially exchanged to the aureus declined from 120 nummi in 293 to only 96 nummi in 300-301.

Civil wars in 306-324 ruined Diocletian's currency. In 309 Constantine reduced the weight of the aureus, henceforth called the solidus (slang for "solid bit") struck at 72 to the Roman pound (4.48 grs.), the standard down to the eleventh century. Silver coins, minted as fractions of the pound, were issued as ceremonial gifts and so disappeared from general use. The nummus was drastically reduced in weight and fineness, falling to a coin of 3.00 grs. and 2% fine by 313 and exchanged at 240 nummi to the Constantinian solidus, representing an inflation of 200% over the official rate of exchange in 307. In the East, 288 nummi were exchanged against the aureus, but the rate was doubled to 576 nummi by the reform of Licinius in 321.

DEBASEMENT OF NUMMUS, 305-348

Average Silver Official

Date Module Weight Content Value

305-307 AE1 10.75 grs.   4.0% 25 d.c.

Apr. 307 AE2 8.00 grs.   4.0% 25 d.c.

Nov. 307 AE2 6.70 grs.   4.0% 25 d.c.

310-313 AE2 4.50 grs.   1.5% 25 d.c.

313-318 AE3 3.36 grs.   1.4% 25 d.c.

318-324 AE3 3.00 grs.   2.0-4.0% 25 d.c.

321-324* AE3 2.40 grs.   0.1% 12.5 d.c.

324-330 AE3 3.05 grs.   1.9% 25 d.c.

330-335 AE3 2.48 grs.   1.0% 25 d.c.

336-337 AE4 1.61 grs.   1.3% 25 d.c.

337-341 AE4 1.64 grs.   1.1% 25 d.c.

341-348 AE4 1.65 grs.   0.4% 25 d.c.

*Eastern nummi of Licinius

Module is classified by descending order of diameter of the nummus so that AE1 = 32-26 mm.; AE2 = 25-21 mm.; AE3 = 20-17 mm.; and AE4 = below 17 mm.

Subsequent efforts to revive a billon currency based on multiples of the nummus, in 348-354 and 362-367, failed. In 371 Valentinian I and Valens demonetized and recoined all billon cons (aes diochonetum or "alloyed bronze") into token bronze coins and pure silver fractions of the solidus.

In 320, Constantine resumed minting pure silver coins on the Tetrarchic standard, based on an argenteus struck at 96 to the Roman pound (3.36 grs.) and tariffed at 1 carat (siliqua) of the gold solidus. The official exchange was 1 gold solidus = silver 24 argentei = 288 billon nummi. Multiple denominations were minted as ceremonial gifts to officials and soldiers:

CONSTANTINIAN SILVER COINS, 320-355

Denomination	Average Weight	Number of Carats	Number per Solidus
Triple Miliarensia	13.44 grams	4.00	6
Heavy Miliarense	5.34 grams	1.60	15
Light Miliarense	4.48 grams	1.25	18
Argenteus	3.36 grams	1.00	24

In 355 Constantius II reduced the weight of argenteus by 50% to 144 to the Roman pound (2.25 grs.); the weights of the higher denominations were lowered accordingly.

WAGES AND PRICES IN THE AGE OF DIOCLETIAN

In early 301 Diocletian issued the Edict of Maximum Prices to halt rising prices, but on September 1, 301 he withdrew the edict and issued a Monetary Edict that doubled the official tariffing of all coins.

WAGES. Military archives from Panopolis in Upper Egypt in 299-300 reveal that a legionary received an annual salary of 1,800 d.c. (= 144 nummi), an allotment of 600 d.c. (= 48 nummi) for grain purchases (annona) and 30 modii (62.5% of his annual needs), and four annual donatives of 2,500 d.c. each (= 200 nummi) for a total payment of 12,400 d.c. The money was paid as 992 silver-clad nummi at the exchange rate of 12.5 d.c. per nummus. In 293 base pay of the legionary was probably reckoned at 1 nummus per day for an annual pay of 360 nummi. The price of wheat was perhaps officially 1 nummus per modius castrensis (= 1.5 modius) so that a soldier's annual minimum of 32 modii castrenses cost 32 nummi or 9% of his annual pay of 360 nummi. Wages in the Price Edict suggests that in 293 a laborer received 1 nummus per day whereas skilled craftsmen received daily wages ranging between 3 and 6 nummi.

PRICES. Inflation in 293-301 cut the buying power of the nummus and drove up prices of all commodities. The scourge of inflation is best seen by converting official grain prices of the Price Edict cited in d.c. into actual coins according to exchange rates in 300-301 (at 12.5 d.c per nummus) and in the Monetary Edict of September 1, 301 (at 25 d.c. per nummus):

Official Grain Prices, 300-305 A.D.

Commodity (modius castrensis)	Official Price	300-301 Price in Actual Coins	301-305 Price in Actual Coins
1 modius, wheat	100 d.c.	8 nummi	4 nummi
1 modius, millet	100 d.c.	8 nummi	4 nummi
1 modius, barley	60 d.c.	4 nummi & 10 d.c.*	2 nummi & 10 d.c.**
1 modius, rye	60 d.c.	4 nummi & 10 d.c.*	2 nummi & 10 d.c.**
1 modius, rice	200 d.c.	16 nummi	8 nummi

*Sum represented by 4 radiate denominations

**Sum represented by 2 radiate denominations

In 301, a legionary bought 32 modii castrenses of wheat officially priced at 256 nummi so that his annual purchase was over 175% his base pay of 144 nummi! Donatives and money supplements for grain purchase reduced this ruinous cost to 26% of his base pay. In 293, his allotment had purchase 2.5 times his minimum needs. The retariffing ordered by the Monetary Edict of 301 immediately halved the actual number of coins paid in purchases and wages but imperial officials and vendors simply recalculated salaries and prices at higher rates of d.c.

In the Price Edict, a farm laborer received daily wages of 2 nummi so that he earned an annual subsistence wage of 720 nummi. His family of four required annually 120 modii of wheat, 120 sextarii of olive oil, and perhaps 720 sextarii of wine. According to the Price Edict, such a family, if it purchased its food needs, spent nearly 1,250 nummi so that the annual subsistence wage would have only defrayed 60% of total costs. Poorer families could lower costs to 1,000 nummi by substituting barley for wheat and radish oil for olive oil.

GRAIN PRICES IN CONSTANTINIAN EGYPT: Market prices of wheat from Egypt (where prices were often half of those elsewhere in the Roman world) reveal steep rises after 305. The price of 2 nummi per modius in 305 doubled to 4 nummi per modius in 312. Debasement and inflation drove up the price to 18 nummi per modius in 314, 40 nummi per modius by 327, 185 nummi per modius by 335, and possibly 320 nummi per modius by 338.