Billon Coinage from Trier

Constantine  RIC VII Trier 208A (in error) VICTORIAE LAETAE PRINC PERP two Victories standing, facing one another, together holding shield inscribed VOT PR on altar	Licinius  RIC VI Trier 825 IOVI CONSERVATORI AVG Jupiter head left, right holding thunderbolt, left transverse sceptre, seated on eagle standing right with wings spread.	Maximinus RIC VI Trier 826 SOLI INVICTO COMITI Sol, radiate, naked to waist, standing with head left in facing quadriga, right raised, left holding globe and whip.

    The billon (roughly 25% percent silver)1 coins above were minted circa 313 A.D. in Trier. Trier was the capitol of Constantine's Gallic Empire, so it would be expected to issue special coinage, like these billon coins. These coins, or Festmünzen, may have been issued to celebrate the short-lived reconciliation of the three Augusti following the defeat of Maxentius in 312. Bruun erroneously listed the Constantine coin as RIC VII Trier 208A.2 The reason that this is in error, is that the billon coinage of 313 was struck by only one officina--so the exergue for the billon coins always reads PTR.  RIC VI erroneously has the second workshop as a possibility for Trier 825.The P of PTR for the billon issue could translate as "struck (percussum)for Trier" or "money (pecuniae) from Trier". In 318 though,when Trier struck base coinage, it had two officinae, so the coins have PTR and STR in the exergue-- prima and secunda or first and second officinae. The reason for the confusion is that the VLPP was re-issued in 318 after a re-tariffing. The 25% billon coinage was short-lived though. In 318, Constantine re-tariffed the coins, giving them 3-5% silver. The VLPP was re-introduced as part of this new higher silver content base coinage. This makes a lot of sense, since many people already associated the VLPP with higher silver content because of the billon issue. So because of the P and S officinae marks, Bruun listed the billon Constantine coin with the later base coins that looked pretty much the same as the billon issues (especially if the base coins were silvered). Maximinus never had a base coin issued though, as he committed suicide after a failed coup attempt in 313. Bruun also listed a bronze medallion with VICTORIAE LAETAE PRINCIPIS PERPETVI (RIC VII 208) with the 318-319 issue, but in the footnotes said that Alföldi thought that this medallion should be dated  immediately after the battle of the Milvian Bridge.3 It seems more likely that this medallion was struck in 313 and was associated with the billon coinage.

Andreas Alföldi, The Conversion of Constantine and Pagan Rome. Translated by Harold Mattingly. New York: Oxford University Press, 1998.
 

¹  this article explains the analysis of the coins and subsequent dating: Barrandon, J. & J. P. Callu & C. Brenot. "The Analysis of Constantinian Coins (A.D. 313-40) By Non-Destructive Californium 252 Activation Analysis." Archaeometry 19 (1977): 173-186.

²Roman Imperial Coinage Volume VII. Spink & Son, 1997, pg 181.

³ Ibid., pg 181.