All that glisters is not gold

The Byzantine Monetary System in the Sixth Century

Solidus

Gold Solidus, ca. 500 AD

The gold solidus (4.55 g) was the basic unit of the coinage, all other coins being valued in relationship to it. The solidus weighed 1/72 of a Roman pound, or 24 carats.

The Constantinian subsidiary coinage in turn collapsed in the early fifth century, at the time of the barbarian invasions. All that survived at the accession of the emperor Anastasius I in 491 was the gold solidus and its two fractions, the half (semissis) and the third (tremissis), and a tiny copper coin known as a nummus, weighing less than 1 gram. In order to provide a stable subsidiary coinage, in 498 Anastasius introduced a series of multiples of the nummus, the chief of them 2 being a copper coin worth 40 nummi and known as a follis.

The typical sixth-century solidus is a coin 20 millimetres in diameter, with a three-quarter or fully frontal bust of the reigning emperor, usually in armour, on its obverse. This representation makes no pretence to being a personal likeness. The reverse initially showed a Victory or an archangel supporting a cross, but Justin II (565–578) preferred a seated figure of Constantinopolis.

Follis

Large bronze follis

The introduction of the large bronze follis, approx. 25 millimetres in diameter and worth 40 nummi, had been the great innovation of Anastasius I in 498. The coin was marked with the Greek letter M, which as a numeral stood for “40,” and it was initially accompanied by only two fractions, a half-follis marked with K (= 20) and a decanummium marked with I (= 10). In 512 the weights of these coins were doubled, and a further denomination of 5 nummi, marked with E, was added; moreover, the minting of nummi, apparently suspended in 498, was resumed.

The relationship of the bronze coinage to the gold (i.e. of the follis to the solidus) was subject to considerable variation. Under Justinian I (527–565), the ratio was at one time 180:1, at another 210:1.

With three denominations of gold and five of bronze, the empire was furnished with a wide range of coins appropriate for the proper functioning of its economy.

Justinian I, in his twelfth year (538/9), further increased the weight of the follis to about 25 grams. This coin, however, was too heavy for convenience, and the weight was reduced to about 22 grams in 541/2. Further reductions took place at intervals over the remainder of the century, so that ultimately the minting of nummi had to be abandoned, and a new unit of 30 nummi, marked with L or XXX, was inserted into the system. Yet even to the end of the century the follis remained a handsome, massive coin whose weight and size must have given its users solid assurance of its value.

Comparative values of solidi and folles in 565 AD
METALDENOMINATIONWEIGHTno. to the
solidus
NUMMIFolles
GoldSolidus nomisma4.55 g18400210
Semissis2.27 g24200105
Tremissis1.50 g3280070
CopperFollis210401
Half-follis420201/2
Decanummium840101/4
Pentanummium168051/8
Nummus840011/40

© 1999, Dumbarton Oaks Research Library and Collection, Trustees for Harvard University. Originally published in Byzantine Coinage, by Philip Grierson.

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