Watch List notes:

THESSALY, Magnetes. Valerian II. Caesar, AD 256-258. Æ Diassarion (22.5mm, 5.41 g, 12h). Bareheaded and draped bust right / The galley Argo left; B (denomination mark) above. BCD Thessaly I –; BCD Thessaly II –; Numismatik Naumann Auction 47, lot 274 (same dies). Dark green patina, natural pit on reverse, some smoothing. Good Fine. The Numismatik Naumann specimen has enough of the obverse legend visible to identify this coin to Valerian II. Extremely rare, perhaps the second known.