Billon antoninianus of Tetricus I, struck at the mint of Colonia Agrippinensium (modern Cologne) during the final years of the Gallic Empire. Obverse: Radiate, cuirassed bust of Tetricus I facing right. Legend: IMP TETRICVS PF AVG Reverse: Salus standing left, holding a patera in the right hand and a rudder in the left, feeding a serpent rising from an altar (altar sometimes absent depending on die). Legend: SALVS AVGG This reverse type emphasizes the health and well-being of the emperors (Augusti), a common propagandistic theme during the politically unstable final phase of the Gallic Empire. Cologne issues of Tetricus I are characterized by simplified engraving and billon fabric typical of the Crisis of the Third Century. Historical Context Tetricus I ruled as the last emperor of the Gallic Empire during a period of severe military and economic stress. His reign ended in AD 274 when he surrendered to Emperor Aurelian, leading to the reintegration of the western breakaway empire into the Roman state. Coins such as this illustrate both the ideological messaging and the declining monetary standards of the late 3rd century.