Constantine I, 307/310-337. Follis (Bronze, 19 mm, 3.61 g, 6 h), a contemporary imitation of an issue from Treveri, after 321. CONSTAN-TINVS [...] Helmeted, draped and cuirassed bust of Constantine I to right. Rev. Altar inscribed with blundered legend; around, blundered legend. Cf. RIC 316 (for prototype). Very fine.
From the Tetrarchy Collection, formed over the past twenty-five years.
This coin is a so-called flip-over double strike, meaning that the flan was not removed between two strikes but flipped over, which resulted in the lower part of the altar being visible on the bust of Constantine on the obverse and the face of the emperor appearing on the altar on the reverse.