Gratian Silver Siliqua

Monetary Context and Denominational System

During the joint reigns of the Valentinianic house, the monetary system was anchored by the gold solidus, struck at 72 to the Roman pound (circa 4.54 grams). The siliqua, theoretically struck at 1/144th of a Roman pound or half a scripulum (approximately 2.27 grams), served as the principal fractional silver denomination alongside the heavier light miliarense (1/72 pound, circa 4.54 grams) and heavy miliarense (1/60 pound, circa 5.45 grams). While gold coinage dominated large fiscal transactions and tax extraction, silver siliquae were produced primarily to fulfill imperial donatives distributed on accessions, five-year imperial anniversaries (vota), and military campaigns. Because official exchange ratios between gold and silver fluctuated according to market bullion prices and state edicts, siliquae often traded as standardized bullion parcels rather than as rigid token fractions, though their purchasing power remained substantial in late Roman military and civil economies.

Mints and Administrative Production

The vast majority of Gratian's silver siliquae were struck in the West, where the primary seat of his court at Augusta Treverorum (Trier) served as the preeminent mint for silver. Marked in exergue with signatures such as TRPS or TRPS dot, Trier maintained an exceptional volume of output to supply the western mobile army along the Rhine. Substantial silver production also occurred at Aquileia (marked AQPS), Rome (VRPS), and later Mediolanum (MDPS). In the Illyrian and Balkan sphere, Siscia (SISCPS) and Sirmium produced limited silver issues. Following the death of his uncle Valens in AD 378, Gratian exercised authority across both administrative halves of the empire before elevating Theodosius I, during which time eastern mints such as Constantinople (CON) and Antioch (ANT) occasionally struck siliquae in Gratian's name. Control marks and mintmarks were consistently positioned in the exergue, occasionally accompanied by letters or symbols in the reverse fields indicating specific officinae.

Obverse Iconography and Imperial Portrayal

The obverse of Gratian's siliquae depicts the youthful emperor facing right. In keeping with late Roman imperial portrait conventions, naturalistic individuality is subordinated to stylized imperial majesty. Gratian is consistently portrayed wearing a pearl diadem or a rosette diadem tied at the back of the head with fluttering ribbon-like ties. He is shown draped and cuirassed, viewed in profile. Early issues struck during his minority alongside Valentinian I and Valens portray a distinctively small bust, whereas issues struck in the mid-to-late 370s and early 380s present a larger, mature bust. Die-cutting styles vary considerably between mints: Trier features fine, delicate drapery and sharp facial contours, Rome displays broader features, and eastern mints adhere to classicizing conventions.

Reverse Designs and Imperial Themes

The reverse typologies of Gratian's siliquae emphasize state preservation, imperial victory, and divine favor. By far the most prolific design is the VRBS ROMA type, depicting the personified city of Roma helmeted and seated on a throne or cuirass facing left, holding a small Victory on a globe in her right hand and an inverted spear or sceptre in her left. This iconography reaffirmed traditional Roman imperial authority and legitimized the court at Trier. Another major series features imperial vota within a laurel wreath, such as VOT V MVLT X (votis quinquennalibus multis decennalibus) and VOT XV MVLT XX, celebrating the completion and anticipated renewal of imperial oaths. Less frequent types include VIRTVS EXERCITVS, depicting the emperor standing with standard and shield, and CONCORDIA AVGGG, celebrating harmony among the co-emperors.

Inscriptions and Epigraphy

Obverse inscriptions on Gratian's siliquae consistently record his imperial titles in standard Latin epigraphy. The dominant formula is D N GRATIANVS P F AVG (Dominus Noster Gratianus Pius Felix Augustus), emphasizing his position as 'Our Lord Gratian, Pious and Fortunate Augustus'. On reverse types, inscriptions reflect the nature of the issue: VRBS ROMA ('The City of Rome'), RESTITVTOR REIP (or REIPVBLICAE, 'Restorer of the Republic'), or votive summaries such as VOT V MVLT X. The exergual mintmarks combine the abbreviation of the city name with administrative prefixes or suffixes such as 'PS' for 'pusulatum' or 'pure silver', verifying the refined metal standard of the issue. Epigraphic styles are generally neat, though letter spacing and serifs vary depending on the workshop and period of production.

Typological Evolution and Chronological Sequence

The production of Gratian's siliquae falls into three broad phases. The earliest phase (AD 367-375) corresponds to his minority under the guidance of Valentinian I. During this period, votive siliquae (VOT V MVLT X) and early RESTITVTOR REIPVBLICAE issues predominated, struck mainly at Trier, Rome, and Siscia. The second phase (AD 375-378) followed Valentinian I's death, marked by the massive output of VRBS ROMA siliquae at Trier to finance military operations against Germanic incursions. The final phase (AD 378-383) commenced after the Battle of Adrianople, when Gratian governed alongside his half-brother Valentinian II and his newly elevated colleague Theodosius I. This phase witnessed continuing VRBS ROMA production, new votive issues (VOT XV MVLT XX), and concurrent emissions honoring the eastern court until Gratian's overthrow by the usurper Magnus Maximus in August AD 383.

Circulation, Hoarding, and Clipping

Siliquae of Gratian circulated throughout the Western Roman Empire and, to a lesser extent, in the East. Their greatest archaeological density occurs in northwestern Europe, particularly in Roman Britain and the northern Gallic frontier. Gratian's siliquae constitute major components of celebrated late Roman British coin hoards, including the Hoxne Treasure and the Dorchester hoard. In late fourth- and fifth-century Britain, as silver inflows ceased following the collapse of the Roman administrative apparatus around AD 407, circulating siliquae were subjected to widespread systematic clipping. People carefully sheared the outer margins to harvest bullion while leaving the central imperial portrait and reverse figures partially intact, resulting in reduced-weight specimens that nevertheless continued to circulate as bullion into the sub-Roman era.

References

1. Coin Hoards and Hoarding in Roman Britain AD 43-c.498. pp. 183-205
2. The Late Roman Gold and Silver Coins from the Hoxne Treasure. pp. 37-52, 85-92
3. Fifth Century Silver Coinage in the Western Empire: The Evidence of the Hoards. pp. 185-198
4. The Roman Imperial Coinage, Volume IX: Valentinian I - Theodosius I. pp. 13-34, 91-108
5. Roman Coins and Their Values, Volume V: The Christian Empire. pp. 301-315