This is not a particularly scarce countermark - Howgego noted 12 and I found seven or so in an acsearch and a few more on vcoins. Apparently there was a shrine to Asclepius in Akmoneia, thus the countermark, supposedly. All the examples I saw were carefully applied along the outside edge so as not to obliterate the emperor's face. So I am guessing this was countermarked during Nero's lifetime. Galba supporters would've whacked him on the nose. Here is an example from the "Automan" collection on FORVM; http://www.forumancientcoins.com/gallery/displayimage.php?album=546&pos=58 Nero Æ 19 Lucius Servenius Capito, Archon & wife, Julia Severa Akmoneia, Phrygia (c. 65 A.D.) [NEPΩN] KAICAP CEBACTOC laureate head right / CEPOYHNIOY KAΠITΩNOC KAI IOYΛIAΣ CEO]YHPAC / AKMONEΩN / Zeus seated left, [owl standing left], EΠI APX [TO Γ] in monograms. RPC 3176. (3.80 grams / 19 mm) Countermark (Obverse): Asklepios standing, holding serpent-encircled staff, in rectangular punch, 4.5 x 9 mm. Howgego 241 (12 pcs). Any other Nero countermarks out there? Or just any new finds - I like looking at them.