Byzantine Coinage: A Thousand Years of the Solidus

Where the line is drawn

Start with the name, because it is misleading. Nobody who struck these coins called themselves Byzantine. They were Romaioi — Romans — and the state that issued the coinage was the unbroken legal continuation of the Roman Empire, governed from Constantinople, the New Rome. "Byzantine" is an early-modern scholarly label, useful for filing but worth remembering as a convenience, not a fact the coins themselves assert.

The conventional opening of the series is administrative, not dramatic: the bronze reform of Anastasius I, dated by most catalogues to about AD 498. Before it, small unmarked bronze (the late-Roman nummus) had collapsed into near-worthlessness. The reform introduced a heavy copper struck in marked, accountable denominations, and that is the point modern reference works treat as the start of distinctly Byzantine money. Anything earlier — Zeno, pre-reform Anastasius — is filed under Roman Imperial coinage in the RIC X volume. The continuity matters more than the label: the gold had not changed at all.

A millennium follows, and it is easier to hold if you break it into phases that the coinage itself records. The Justinianic age (Justin I through Maurice, roughly 518–602) is the reconquest and the great dated bronze. The Heraclian crisis (from 610) is the loss of Syria and Egypt to the Arab conquests and a sharply contracting mint network. The Isaurian iconoclasm (Leo III onward, from 717) strips saints and, for a time, even Christ from the dies. The Macedonian renaissance (Basil I to Basil II, 867–1025) is the splendid gold. Then the Komnenian reform of 1092 rebuilds the whole system, the Fourth Crusade shatters it in 1204, and a reunited but shrinking Palaiologan empire coins thin silver until Constantinople falls in 1453. One tradition, but not one straight line.

The gold that did not move

The spine of the system is a single coin that barely changed for seven hundred years: the gold solidus of Constantine, about 4.5 grams, effectively pure, struck at one seventy-second of a Roman pound. As the empire's working language shifted to Greek it came to be called the nomisma, the same coin under a different name, and it was the most trusted money in the medieval world — from Frankish Gaul to the Indian Ocean, merchants took the Byzantine gold piece on sight. Below it sat the half-solidus (semissis) and the third-solidus (tremissis), the tremissis being the standard small gold payment of the early period.

The bronze is where attribution actually happens, and it is where Anastasius's reform shows. The reverse carries a large Greek numeral giving the coin's value in nummi: M for the 40-nummi follis, the roughly nine-gram workhorse copper; K for the 20-nummi half-follis; I for the 10-nummi decanummium; E for the 5-nummi pentanummium. Below the value letter sits an officina letter; the mint abbreviation usually sits in the exergue. Then Justinian added the single most useful chronological gift in ancient numismatics. In 538 he ordered the regnal year stamped on the bronze — ANNO followed by a numeral — so a great many sixth- and seventh-century folles can be dated to the year. Read the big letter, read the mint, read the year. That sequence attributes most Byzantine bronze.

Silver was always the weak leg. The late-Roman siliqua and the ceremonial miliarensis carried into the early period but never did the daily work that Roman imperial silver had. Heraclius struck a heavier silver coin, the hexagram, from around 615 — six to seven grams of metal raised, in part, to pay for the war against Sasanian Persia, the Sasanian superpower on the eastern frontier. The seventh century then narrows everything. After the Arab and Slav invasions the mint network shrinks toward Constantinople and Syracuse, bronze weights wander, and the careful accountable copper of Anastasius becomes, for a while, a rough local product.

The system was rebuilt once. Around 1092 Alexios I Komnenos replaced the debased eleventh-century gold with a new structure: the gold hyperpyron (about 4.45 grams, struck at roughly 20.5 carats fine rather than the old 24), an electrum and a billon aspron trachy on cup-shaped flans, and a small bronze tetarteron. The thousand-year solidus standard ended there. What came after was slow decline: progressive debasement under the Palaiologoi, a silver basilikon introduced around 1300 in open imitation of the Venetian grosso once Italian money had taken over Mediterranean trade, and finally thin, local, late coinages struck almost in the shadow of 1453.

The denominations

The working vocabulary, gold first, then the metal that does the attributing. NumisLens does not catalogue these yet — the weights are reference figures, not inventory.

Denomination	Metal & rough weight	What to know
Solidus / Nomisma	Gold, ~4.5 g	The backbone, Constantine to the eleventh century. Same coin; the Greek name takes over from Heraclius on.
Semissis / Tremissis	Gold, ~2.2 g / ~1.5 g	Half and third solidus. The tremissis was the everyday small gold of the early period.
Hyperpyron	Gold, ~4.45 g	The post-1092 gold standard, debased to about 20.5 carats. Often cup-shaped.
Follis (M)	Bronze, ~9 g	The 40-nummi workhorse. The reformed Anastasian copper; usually the coin a collector handles first.
Half-follis (K) / Decanummium (I) / Pentanummium (E)	Bronze, smaller	20, 10, and 5 nummi. The value letter and, after 538, the regnal year do the dating.
Miliarensis / Siliqua	Silver	Late-Roman inheritance, more ceremonial than commercial. Fades through the seventh century.
Hexagram	Silver, ~6–7 g	Heraclius's war silver from around 615. The one period silver struck at scale.
Aspron trachy / Tetarteron / Basilikon	Electrum, billon, bronze, silver	The post-reform vocabulary. Trachea are the cup-shaped pieces; the basilikon is the late Venetian-style silver.

One practical caution. Late Byzantine billon trachea are abundant, ugly, and badly struck — double-struck, off-flan, the type half missing. Beginners buy bags of them cheap and then cannot attribute a single one. Buy fewer, better coins. A clear regnal-dated Justinianic follis teaches more than a hundred Palaiologan scyphate scraps.

Dynasties, not one long line

Byzantine coinage is read by ruling house, the way Roman is read by emperor, and the houses each have a numismatic signature. The Justinianic dynasty (the Justinian dynasty — Justin I, Justinian I, Justin II, Tiberius II, Maurice) is the great age of dated bronze and gold from every active mint; Justinian I alone leaves one of the largest numismatic legacies of any ancient ruler. The Heraclian house (the Heraclian dynasty — Heraclius, Constans II, Constantine IV, Justinian II) gives us the multi-emperor family obverses and, in the 690s, the first imperial coin to put Christ Pantokrator on the obverse — Justinian II's solidus, a turning point in what a coin could show.

Then the Isaurians strip the imagery back to the cross-on-steps in the iconoclast decades, and the Macedonian house reverses that completely. The Macedonian gold (the Macedonian dynasty — Basil I, Leo VI, Constantine VII, Basil II) is the aesthetic peak: Christ enthroned in full, the emperor crowned by the Virgin, struck on broad clean flans. After that the Komnenian reformers rebuild the currency, the Crusaders sack the capital in 1204, and the splintered successor states — Nicaea, Trebizond, Epiros — each strike their own gold and trachea before the Palaiologoi reunite Constantinople in 1261 and coin a slowly impoverishing silver down to the last emperor, Constantine XI, in 1453. The dynasty hubs and the emperor pages above carry the per-house detail as they are published.

Which reference to attribute from

For Byzantine attribution the working trio is the Dumbarton Oaks Catalogue (DOC) and Hahn's Moneta Imperii Byzantini (MIB) for scholarly depth, with Sear's Byzantine Coins and Their Values as the one-volume collector reference most dealers cite by SB number. Reach for those rather than this page, because the NumisLens structured catalogue is built on Roman and only being extended outward — the Byzantine series is on that road but not on it yet. That is the reason this hub, unlike the Roman ones, links to no per-emperor or per-denomination inventory: the inventory does not exist here, the public canonical inventory already does and is excellent, and the sensible move is to point you straight at it. Within NumisLens, the related reference is the Roman precursor at Roman Imperial coinage, the Greek tradition that runs alongside the eastern provinces at ancient Greek coinage, and the forthcoming Sasanian coinage hub for the rival empire on the other side of the war Heraclius's hexagram paid for.

Collecting and the market

Here is the anchor: a common Justinianic or Heraclian Constantinople-mint solidus in Extremely Fine runs roughly four hundred to twelve hundred dollars — full Roman-imperial weight and gold, at a fraction of what a comparable Roman aureus of the same eye-appeal costs. That gap is the whole pitch for the series. Scarce mints and types sit well above that; Macedonian nomismata of Basil I through Basil II sit higher, several hundred to a few thousand for sharp pieces. Bronze is the entry point and stays cheap — presentable Anastasian and Justinianic folles in Very Fine often trade for the price of a couple of paperbacks, and a crisp regnal-dated follis with a readable mint is a genuinely satisfying coin for very little money. Komnenian and Palaiologan hyperpyra and trachea fall in the low-to-mid hundreds.

A few field habits worth keeping. Gold solidi were widely clipped in antiquity for their metal, so check that the coin is full-weight and full-flan before you pay a full-flan price. "Graffiti" — contemporary scratched marks — is common on Byzantine gold and depresses value, fairly. The mint and the regnal year change the price more than the grade does on bronze, so learn to read them before you buy. The major auction houses for the series are CNG, Roma, Leu, and Nomos; their archives, searchable on acsearch, are the best price guide that exists. The reference collections are Dumbarton Oaks — the canonical one — the British Museum, and the American Numismatic Society's collections database. Buy from sellers who publish provenance, and keep your own records as carefully as the empire kept its weight standard.

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