Watch List notes:

The Roman Empire
Regalianus, 260 – 261

Antoninianus, Carnuntum 260-261, AR 3.00 g. IMP C P C [REGALIANVS] AVG Radiate and draped bust r. Rev. PROVIDENTIA AVG Providentia standing l., holding ears of corn and cornucopiae; at her feet, modius filled with corn ears. C 5. RIC 8. MIR A3.
Very rare. Usual traces of overstriking (on denarius of
Septimius Severus). Light tone and very fine

Ex Lanz sale 154, 2012, 468.
This coin is of special interest as the obverse die of Regalian (A3) was struck directly over a portrait of Septimius Severus on a denarius whose face still dominates the center of the obverse. The overstruck portrait of Regalian is clearly visible, providing the back of the head, and the outline of the face of Regalian is visible before the nose of Septimius Severus. AMP.