A Hoard of Protomiliarenses (?) of Constantine I with Crispus and Constantine II Caesars found near the Northern Fortress Wall of Serdica

Abstract

In 2019, a hoard of 92 identical coins, struck from the same pair of dies at the Sirmium’s mint, was discovered during the archaeological excavations north of the Serdica’s fortress wall. These coins were minted in 320, and were hidden soon after in a shallow pit next to a wooden pillar of a building within the so-called northern extension of the city – Serdica II. The ongoing political crisis in the Roman Empire at the time, particularly the conflict between Emperor Constantine I (r. 306–337) and Emperor Licinius I (r. 308–324), was the likely reason for the hoard to be deposited in the ground.
The coins belong to the CONSTANTINVS MAX AVG and CRISPVS ET CONSTANTINVS CC, SIRM type, corresponding to RIC VII, 14 (Bruun 1966, 469), and were initially classified as miliarenses (Стоянова 2020, 761). Numismatic catalogues describe them as “small medallions”, despite the absence of any ceremonial imagery. The discovery of an entire series of identical specimens strongly suggests that they were part of the regular monetary system rather than ceremonial issues.
X-ray analysis reveals that the coins contain only small amounts of silver, 2–3% in the core and up to 6.4% near the surface. The total ratio of white metals (silver, tin, lead and antimony) is about 14% in the core and up to 30% near the surface, indicating that they underwent additional acid pickling to create a silver appearance. Their composition and manufacturing align more closely with folles than with miliarenses, but their weight (average 6.50 g) is double that of their contemporary folles, which had already been reduced in mass to 3.40 g by that time. Given this, we suggest that these coins represent a distinct or transitional denomination – possibly a “protomiliarenses”. Based on economic analyses of the period, we estimate their value at 50 denarii communes each (the accounting unit standardised after Diocletian’s Edictum de Pretiis in 301), or a total hoard value of 4,600 denarii communes.