Constantine IV (668 AD–685 AD) — Byzantine Emperor

Eldest son of Constans II, Constantine IV inherited the throne in September 668 when his father was assassinated in a bathhouse at Syracuse during the western expedition that had taken the imperial court out of Constantinople for the previous five years. The reign that followed was defined by a single emergency, the first sustained Arab siege of Constantinople from 674 to 678 (conducted as an annual summer naval campaign by the fleets of Mu'awiya I), and its resolution, in which the Byzantine defenders deployed a new naval incendiary weapon the contemporary sources call the liquid fire and modern historians call Greek fire, the chemistry of which remains contested. The siege broke in 678, a thirty-year peace was concluded with the Caliphate, and in 680–681 Constantine IV convened the Third Council of Constantinople, the Sixth Ecumenical Council, which condemned Monothelitism and closed the seventy-year doctrinal rift the Heraclian compromise of 638 had opened.

The defeat of the first sustained Arab siege of Constantinople between 674 and 678 is the political event that determines the survival of the Byzantine empire into the medieval period. Constantinople had come within months of falling, the siege-era gold and silver of those four years documents an empire striking metal under naval blockade, and the thirty-year peace of 678 fixed a frontier the Caliphate would not seriously breach again until the second siege under Leo III in 717. Separately, the obverse change from the three-figure dynastic solidus to the solo-portrait solidus around 681, executed in response to the demotion of Heraclius and Tiberius, is one of the cleanest numismatic records of intra-dynastic succession politics in Byzantine history; the gold of the reign carries the before-and-after of a documented palace decision on its face.

Key Events

15 September 668 AD Constans II is assassinated in the bathhouse at Syracuse; Constantine IV, holding Constantinople as senior co-emperor in his father's absence, succeeds without serious challenge after the brief revolt of Mizizios in Sicily is suppressed by Western forces

674–678 AD First Arab Siege of Constantinople. The Umayyad fleet of Mu'awiya I conducts annual summer naval campaigns against the capital from forward bases at Cyzicus; the defenders deploy the naval incendiary later called Greek fire, the chemistry of which remains debated in modern scholarship

678 AD Thirty-year peace concluded with the Umayyad Caliphate after the failure of the siege; the Caliphate withdraws from Cyzicus and pays an annual tribute, the first such reversal of Arab momentum since the loss of Syria in the 630s

680–681 AD Third Council of Constantinople: the Sixth Ecumenical Council, convened by Constantine IV in the imperial palace, condemns Monothelitism and closes the doctrinal rift opened by Heraclius's Ekthesis of 638 and Constans II's Typos of 648

681 AD Defeat in the Bulgar war south of the Danube and recognition of the Bulgar khaganate of Asparuh as a tributary polity north of the Haemus mountains; this is the founding event of what becomes the First Bulgarian Empire

c. 681 AD Removes his younger brothers Heraclius and Tiberius from co-emperorship and from the gold coinage, demoting them in the dynastic-solidus series after years of three-figure obverses

September 685 AD Dies in Constantinople of dysentery at roughly thirty-three years of age; succeeded by his sixteen-year-old son Justinian II without dispute

Coinage

The gold coinage of Constantine IV is the cleanest numismatic record of intra-dynastic succession politics anywhere in Byzantine history, because the obverse composition of the solidus changes within the reign in direct response to a documented political event. The early issue follows the late-Constans II pattern of a three-figure dynastic solidus: Constantine IV at centre on the obverse, his younger brothers Heraclius and Tiberius flanking him as junior co-emperors, the three crowned facing busts struck on the standard 4.45g module at the Constantinople workshops. Around 681, after the doctrinal settlement at the Sixth Ecumenical Council and in the context of an army demand that the brothers be removed, Constantine demoted Heraclius and Tiberius from the co-emperorship and they vanish from the obverse; the late issue carries Constantine alone in a frontal helmeted cuirass-bust, the brothers retained only as the standing flanking figures on the reverse beside the cross potent on three steps. The bronze continues the post-659 Constans II convention of an undated heavy M-follis without a regnal year in the exergue; the year-dating system introduced by Justinian I in 538 had been abandoned by Constans II around 659 and was not restored under Constantine IV. The mint network of the reign reflects the still-substantial Western Byzantine footprint inherited from the Syracusan court (Constantinople, Thessalonica, Carthage, Ravenna, Rome, and Syracuse all sign output, with a brief Sardinian phase), and a parallel silver hexagram tradition continues at Constantinople and Syracuse with the legend DEUS ADIVTA ROMANIS. The reference framework is Grierson's Catalogue of the Byzantine Coins in the Dumbarton Oaks Collection Vol. II.2 (Phocas to Theodosius III, 602–717) and Sear's Byzantine Coins and Their Values (2nd ed., 1987) for the working pricing reference.

Denominations

Gold Solidus Gold Semissis Gold Tremissis Silver Hexagram Bronze Follis (M, undated post-659 tradition) Bronze Half-Follis (K) Bronze Decanummium (I)

Notable Types

Three-figure dynastic solidus: crowned facing bust of Constantine IV at centre flanked by smaller crowned busts of his brothers Heraclius and Tiberius, reverse cross potent on three steps between two standing figures, legend VICTORIA AVGU and officina mark (Constantinople, c. 668 to c. 681, the standard issue of the first two-thirds of the reign and the densest surviving Constantine IV gold)
Solo-portrait solidus: Constantine alone on the obverse, helmeted cuirass-bust facing holding spear and shield, the brothers reduced to the flanking standing figures on the reverse beside the cross potent (Constantinople, post-c. 681, the issue struck after the political demotion of Heraclius and Tiberius, scarcer than the three-figure series)
Silver hexagram: facing bust of Constantine on the obverse, cross potent on globe on three steps with legend DEUS ADIVTA ROMANIS on the reverse (Constantinople and Syracuse, the continued post-Heraclius silver tradition, struck on a thinner module and surviving in lower numbers than the gold)

Common Reverses

Cross potent on three steps between two standing figures (the brothers Heraclius and Tiberius retained on the reverse even after their removal from the obverse), legend VICTORIA AVGU and officina letter, on the solidus across the whole reign Large M (40 nummi) flanked by mint signature, no regnal year in the exergue, on the bronze follis: the undated post-659 tradition inherited from Constans II and continued without modification Cross potent on globe on three steps with legend DEUS ADIVTA ROMANIS, on the silver hexagram at Constantinople and Syracuse

Active Mints

Constantinople (CON) Thessalonica (TES) Carthage (KART) Ravenna (RAV) Rome (ROMA) Syracuse (SCL) Sardinia (briefly, the Cagliari workshop active under Constans II and into the early years of Constantine IV)

Collecting Guide

Cross-collector demand on Constantine IV runs through buyers who would never describe themselves as Byzantine specialists: Greek-fire and first-Arab-siege historians, early-Bulgarian-history collectors, and the political-numismatic pair-collectors after the 681 demotion. That demand structure means the gold prices off the dynastic-portrait sequence rather than off grade alone. The working catalogue references throughout are DOC Vol. II.2 (Grierson) and Sear's Byzantine Coins and Their Values; NumisLens does not maintain a per-emperor record for the seventh-century Heraclian gold. Common Constantinople solidi of the three-figure dynastic type (c. 668 – c. 681) sit in the $400–$1,000 band in VF and $1,200–$2,500 in EF at CNG, Roma, Künker, Heritage, Leu, and the dedicated Byzantine sales at Stack's Bowers; the rarer solo-portrait solidus struck after the c. 681 demotion of Heraclius and Tiberius carries a clear specialist premium of perhaps fifty to a hundred percent over the three-figure issue at comparable grade. Within the three-figure series, the siege-era issues of 674–678 (and especially the parallel Syracuse and Sardinia mint outputs struck while Constantinople was under naval blockade) attract specialist demand from collectors who pursue the documentary connection to the first Arab siege. The silver hexagram is scarcer in surviving numbers and trades at $300–$800 in VF; Carthage and Ravenna gold sit at a meaningful premium over the Constantinople output for the regional Western Byzantine specialist field. Bronze folles are the accessible entry surface at $40–$150 across the major mints in VF.

Market Overview

Constantine IV draws specialist demand from two distinct cross-collector fields: medieval-history collectors who pursue the gold and silver of 674–678 for the Greek-fire and Constantinople-siege narrative, and Eastern European numismatic specialists who collect the late reign for its documentary connection to the recognition of Asparuh's Bulgar khaganate in 681, the founding event of the First Bulgarian Empire and a reference point for the modern Bulgarian numismatic field. The dynastic-solidus demotion sequence has emerged as a third collecting axis in recent auction cycles, with paired three-figure and solo-portrait solidi acquired together for the political-numismatic narrative. Provincial mint outputs at Syracuse, Carthage, and Ravenna trade steadily at a modest premium over Constantinople pieces of identical grade.

Constantine IV

Key Events

Coinage

Collecting Guide

Market Overview

Related Resources

Further Reading