Why did Become Cup-shaped in the XIth Century?

Mike Markowitz Washington Ancient Numismatic Society

Michael IV Gold Nomisma Constantinople 1034-1041 Sear 1824

1

For centuries, beginning about 312 AD with , the gold coins struck by the Eastern Roman empire at Constantinople were a standard of purity and value, accepted in trade throughout the Old World. They have been found in hoards in Scandinavia, brought home by Vikings who served in the Imperial guard. They have been found deep in Central Asia, India and even China. In the West, long as Latin was the language of commerce these coins were called “solidi”. As Latin declined, they came the be called “bezants,” and many other names. Beginning in the 11th century, the gold coins gradually became concave. By the middle of the 12th century they were deeply cup-shaped. Historians and numismatists have offered various explanations for this strange transformation. This presentation will review some of these theories and suggest a possible answer that makes sense in terms of what we know about metallurgy and basic engineering principles.

1 The Problem • Beginning around 1045, Byzantine gold coinage became concave (cup-shaped). • By c.1070 this became more extreme, and extended to the silver alloy and eventually even low-value copper coinage. • This shape persisted through the currency reform of Alexios Komnenos (1091) and the Latin occupation of Constantinople (1204-1261). • Concave coins were more labor-intensive to strike, but were issued well into the 14th century, when regular gold coinage ended (John VI, c.1353).

2

Why did they go to all the trouble of striking coins that were so difficult to produce?

2 E udocia Makrembolitissa R. 21 may-31 dec 1067

Gold histamenon nomisma of Constantinople, Sear 1857, DO 1. (4.37 g. 26mm) about EF, Scarce. Reverse struck from worn dies, graffiti in rv field left between heads (Monogram for “Michael?”) Obv: +his XIS ReX RegnanTinM - “Jesus Christ, King of Kings.” Facing nimbate Christ enthroned, left hand holding Gospel book and raising right hand in benediction. Rev: +MIX EV !" "#$S - “Michael, Eudocia, Constantine.” Eudocia crowned wearing loros and holding scepter between sons Michael (VII) left and Constantine right, each holding globus and akakia.

Note that the faces of the three standing fugures on the concave side are heavily worn. This cannot be circulation wear, since they are protected by the rim of the coin. The facial details on the die itself must have been worn down.

3

From the author’s collection, 600 dpi flatbed scanned image.

3 Why they did it: Some Theories

Wroth (1908) “Two distinct fabrics” for different denominations that differ by only one-twelfth: the flat tetarteron (~4.05 g.) and the concave histamenon (~4.4 g). Grierson (1982) “By that time [c. 1100] the coins were also concave, which rendered them less liable to bending or crumpling.” Various: Cup shaped coins (a.) Stack better; (b.) Jingle more pleasantly in a purse. (c.) Are better for playing tsikaki (a Greek version of tiddly-winks).

4

Wroth, W. Catalogue of the Imperial Byzantine Coins in the British Museum (1908) p.liii Grierson, Philp. Byzantine Coins. U. of California Press (1982) p.15 “A French numismatist once noted in all seriousness that that the form might have been intended to facilitate the playing of some Byzantine progenitor of the modern Greek tsikaki, a kind of tiddly-winks (P. Bordeaux in Revue Numismatique 4, 1 [1897] P.V. xiii-xiv) since modern five and ten lepta pieces were often hammered into this form by users in the hope of improving their chances of winning. “ Grierson, Dumbarton Oaks Catalog Vol III, Part 1, page 6, note 3

4 Just to review…

Concave Convex (the side (the side that’s that’s dished-in) dished-out) Technical Technical Obverse Reverse (lower die (upper die “Anvil”) “Punch”) 5

Nothing is ever simple in Byzantine numismatics. On most cup-shaped issues, the convex face bears the portrait of Christ or the Virgin, and would be considered the more important “type” (typological obverse) while the concave face bears the portrait of the ruler and would be considered the less important type (typological reverse). The religious icon on the convex side takes most of the wear and tear from circulation, while the imperial image is protected from circulation wear by the high rim.

5 Nummi scyphati “…the common description of such coins as , on the assumption that the eleventh century word scyphatus was derived from the Greek %&'()´ ! (‘cup’) and referred to them was incorrect. Histamena are described in south Italy as scifati as early as 1024, before the concave fabric had been introduced, and the true etymology of the word is shuffi or shiffi from Arabic, shafah, meaning an edge or rim, referring to the conspicuous border on… Basil II’s histamena… Grierson, Byzantine Coins (1982) p.198

6

Illustration from CoinArchives.com: Gold Histamenon nomisma of Basil II 976 - 1025, Constantinople, 1005-1025, 4.45g, DOC 6a, Sear 1800, Gorny & Mosch, Auction 164, March 17th, 2008, Lot 487

6 Skyphos

A deep, stemless drinking cup... The Corinthian type is characterized by its inward curve of the lip. In the Attic types, the lip is slightly concave and the foot is heavier (Type A illustrated here). During the fourth century [BC] both types grow narrower and more concave in the lower part of the body. Both the Corinthian and the Attic skyphos enjoyed long popularity, from the early black figure down to the Hellenistic period.

7

Source: www.mysteriousetruscans.com/art/pottery.html

7 Increasing Diameter

Year Avg. Dia. of Histamenon (mm)

1030 24 (Romanus III) 1035 26 (Michael IV) Beginning of Debasement 1040 27 (Michael IV) 1045 28 (Constantine IX) Beginning of Concavity 1050 28 (Constantine IX) 1055 25 (Theodora) Reversion to flat form 1060 27 (Constantine X) 1065 28 (Constantine X) 1070 28 (Romanus IV) 1075 29 (Michael VII) 1080 30 (Nicephorus III)

1085 31 (Alexius I) 8

Data from Dumbarton Oaks Catalog II and III

8 Debasement of the Gold

Year Typical histamenon (carats) 24 kt is 1030 22-23 (Romanus III) pure gold 1035 23! (Michael IV) 1040 19! (Michael IV) 12 kt is 1045 20 (Constantine IX) ~50% silver 1050 19! (Constantine IX) 1055 18! (Theodora) 1060 17!-19 (Constantine X) 1065 18 (Constantine X) 1070 16-18 (Romanus IV) 1075 12 !-14 (Michael VII) 1080 9 (Nicephorus III) 9

after Grierson, DOC III, part 1, page 40, Table 3

9 Positive Feedback Loop

Specific Gravity Gold: 19.32 Silver: 10.49 Debasement Increased Diameter • Less Gold, More Silver •Reduced Intrinsic Value • Thinner flan •Alloy more brittle •More impressive coin

10

Gold is much more dense than silver, If we replace some of the gold in a coin with silver, while trying to hold the coin weight constant, then the volume of metal will increase. We must either make the coin thicker (holding the diameter constant) or larger (holding the thickness constant), or some combination of the two.

10