Aezanis, Temple of Zeus, 117-138 AD 
History/Medieval Studies 303
Early Medieval and Byzantine Civilization: Constantine to Crusades



 Book List 
 Discussion Topics

 Imperial Crisis 
 Later Roman Emperors, 306-395 
 Fall of Western Empire 
 Age of Justinian 
 Islamic Caliphs 
 Byzantine Dark Age 
 Triumph of Christianity 
 Macedonian Resurgence 
 Restoration and Ottoman Advance 

 Finances under Justinian
 Byzantium c.850A.D.


I. Cost of Justinian's Wars
II. Estimated Revenues and Reserves
III. Currency Manipulation

Based on recorded and estimated costs of military operations and diplomacy, the following is an educated guess of the price tags of Justinian's major wars of reconquest.  It is, as yet, difficult to estimate the costs for minor wars such as the intervention in southern Spain, the defensive operations in the Balkans, or the Lazic War in the Caucasus.

Cost of Military Operations, 527-531
Cost of Persian Treaty, 532
Revenues lost to Chosroes, 540
Cost of Rebuilding Antioch
Cost of Military Operations, 540-544
Cost of Truce of 545-551
Cost of Truce of 551-556
Cost of Truce of 561/2


1,000,000 solidi
   792,000 solidi
     72,000 solidi
   360,000 solidi
2,000,000 solidi
   144,000 solidi
   187,000 solidi
   210,000 solidi

4,765,000 solidi

Expedition of 532-533
Costs of Restoring Prefecturate
Cost of Military Operations, 539-544
Cost of Military Operations, 544-548


4,000,000 solidi
   500,000 solidi
1,000,000 solidi
2,500,000 solidi

8,000,000 solidi

Cost of Military Operations, 535-538
Costs of Restoring Prefecturate
Cost of Military Operations, 544-548
Cost of Military Operations, 552-554
Costs of Restoring Prefecturate


  6,000,000 solidi
     500,000 solidi
  4,000,000 solidi
10,000,000 solidi
  1,000,000 solidi

21,500,000 solidi

Eastern Policy
Victory in North Africa
Victory in Italy
Other Offensive Operations (Lazic War,
Spanish campaign, operations in Balkans)


  4,765,000 solidi
  8,000,000 solidi
21,500,000 solidi
   2,000,000 solidi
 35,765,000 solidi


Justinian (527-565) is reported to have inherited a surplus of 28,800,000 solidi (400,000 pounds of gold), which had been amassed by Anastasius I and Justin I.  Most of this surplus was probably still available in 533 when Belisarius conducted the invasion of Vandal North Africa (minus the subsidy to Chosroes I and expenses of the First Persian War).

The annual income of Justinian in c. 555, after the recovery of the western provinces, is estimated as follows:

Prefecturate of the East
Prefecturate of Dacia and Illyricum
Prefecturate of Africa
Prefecturate of Italy


5,000,000 solidi
   100,000 solidi
   480,000 solidi
   420,000 solidi

   6,000,000 solidi

Prior to 548, Justinian could not count on any surplus revenues from Africa, and prior to final victory in Italy (554) he could seldom obtain surplus revenue from the Italian Prefecturate. Prior to 555, his total annual income was perhaps 5,000,000 solidi, but at least 80% of this income was committed to meeting fixed administrative, military, ceremonial, and religious costs. At most, only 1,000,000 solidi were available each year to meet the extraordinary costs of overseas operations in Italy and Africa, offensive operations in Mesopotamia, or treaties purchased from the Persians.

Although the figures are much too uncertain to give anything like an accurate budget, the total of extraordinary costs compared against the annual surplus revenue plus the surplus amassed by Anastasius indicate that between 540 and 545 A.D. Justinian must have faced a financial crisis.  His costs were far exceeding his surplus income, and there was little or no remaining surplus of stockpiled gold solidi.


Since the reforms of 498 and 512, the imperial government employed a currency based on the gold SOLIDUS, minted at 72 to the Roman pound (4.48 grs.), and a fractional currency of bronze denominations based on a follis (tariffed at 40 nummia).  In 527 the exchange was 1 solidus = 210 folles = 8,400 nummiae.  As military and diplomatic costs mounted after 540, Peter Barsymes devised ingenious means to stretch the supply of currency.


In 538/9 Justinian increased the weight of the follis from 13.5 grs. to 22.00 grs. (with a diameter of 42 mm.) and revalued the solidus from 210 to 180 folles.  In 542-555, Peter Barsymes economized by steadily reducing of the weight the follis from 22.0 grs. to 16.00 grs., a loss of 27% of its weight, but the imperial government imposed the exchange rate of 1 solidus to 180 folles.


Justinian minted solidi at 98.5% fine so that there was, at most, a minor debasement of 1% from the ideal standard, so that the claims of Procopius (Anc. 22. 38) are exaggerated.  In the early 540s, Peter Barysmes introduced gold coins known as "light weight solidi;"  The imperial mint at Constantinople struck solidi of pure gold that are clearly marked as weighing 23, 22, or 20 siliquae ("carats") rather than the full 24 siliquae. Since solidi were minted at 72 to the Roman pound, the state made the following profits.

If 72 solidi were minted at 23 siliquae, only 1,656 siliquae of gold were consumed rather than 1,728 consumed for striking full weight solidi.  The surplus yielded 3 extra full weight solidi.  If solidi were minted at 22 siliquae to the pound, then the surplus was doubled to 6 full weight solidi; if minted at 20 solidi, the surplus was doubled again to 12 full weight solidi.

The potential savings can be seen in a simple example.  If the mint was ordered to remint half of the 2,016,000 solidi received in taxation as light weight coins the following surplus of full weight solidi was obtained for each weight standard:

Wt. Standard
23 siliquae
22 siliquae
20 siliquae
Surplus Full Wt. Solidi
  42,000 solidi
  84,000 solidi
168,000 solidi

With sums of 42,000 to 168,000 solidi, Justinian could buy the services of the Lombards or a treaty from Shah Chosroes.

Dr. Kenneth W. Harl 
Office: History 211 (504)862-8621 
Fax: (504) 862-8739 
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 Tulane University
Last updated 03/19/98
by Annette Lindblom