That's a handsome coin. I spent some time trying to figure out a rough one in my collection - anchor or crossed cornucopiae seem to be the choices for the countermark. I'd guess anchor for yours, but that's only a guess. Here is mine, far too pitted to make out for sure: Kingdom of Commagene Æ 25 Iotape (Antiochus IV consort) (c. 66-72 A.D. - Straight Edge) Samosata Mint BA[ΣIΛIΣΣA IΩTAΠH ΦIΛAΔEΛΦOΣ], diademed and draped bust right / KOMMAΓHNΩN, around scorpion, all within laurel wreath. RPC I 3858; BMC Iotape 4. (15.72 grams / 25 x 24 mm) eBay May 2021 Lot @ $2.88 Countermark: Countermark anchor (?), in 5-6 mm irregular circle or square. Howgego 372 Countermark is not entirely clear on this specimen. This issue often found countermarked with these: Cornucopiae: Howgego 403 Anchor: Howgego 372
Again, thank you for this information, @Curtis - you solved my numismatic "brick wall" (as the genealogists call them). Here is a photo of mine compared with the clearest of the RPC examples and a new and improved attribution (Howgego says the countermark is for Nero, which is pretty cool). I'd say this is a pretty good match for both host and countermark: Claudius / Nero CM Æ 22 Alexandria ad Issum, Cilicia n.d. (c. 40-41 / 43-44 A.D.) Alexander the Great, diademed and draped bust right / [ΑΛΕΞΑΝΔΡΕΩΝ ΕΤ ΙΡ], Dionysus standing, left with cantharus and thyrsus; panther to left. (9.85 grams / 22 mm) eBay Dec. 2019 Lot @ $3.13 Host Coin Attribution: RPC I, 4075; Levante, NC 1971, 99, nos 64–70 Countermark: Obverse, NE in 10 x 6 mm oval. Howgego GIC 552; RPC Countermark Type 681. Howgego attributes this to Nero, notes dates 40/41 (1) and 43/44 (2); ? (1).
Oh, just remembered -- here's another neat countermark. This one is actually cited (but not illustrated) in Howgego GIC 686 (as Robert 77 = this coin): Roman Provincial. Cilicia, Hierapolis-Castabala. Faustina Junior (Augusta, 147-175 CE) Æ Triassarion (29mm, 10.11 g, 6h). Temp. Marcus Aurelius, 161-180 (or Antoninus?). Obv: ΦΑΥϹΤΙΝΑ ϹƐΒΑϹΤΗ. Draped bust right, wearing crescent on forehead. Rev: ΙƐΡΟΠΟΛΙΤΩΝ. Radiate Helios, otherwise nude, standing left, raising hand and cradling scepter; lighted torch to left; countermark: T in incuse. Ref: RPC (IV) 4976.6 (this coin); SNG von Aulock 5572 (this coin); SNG Levante 1586 (this coin); Robert 27, pl. XXVI No. 77 (this coin). Countermark: Howgego 686 (this coin cited). Prov: Ex Edoardo Levanted Collection, #1586; Hans von Aulock Collection, #5572; CNG 504 (2021 Nov 17), Lot 204. Something else interesting, you can see that the countermark caused it to crack because it was applied opposite the high-relief portrait. Besides being where people look first, another benefit of placing countermarks on the obverse of Roman Provincials is the lower-relief reverse provides a flatter surface for the coin to rest upon while being struck.
That is a lovely example; countermarked coins tend to be quite beat up. I have one too, but not-so-lovely. It seems to have an additional countermark to the "T" but I was not really sure about it, as can be seen from my attribution efforts: Faustina II Æ 26 Hierapolis-Castabala, Cilicia (c. 146-180 A.D.) [ΦAYCT]INA [CEBACTH], crescent over draped bust right, / IEΡ[OΠOΛITΩN] Helios stdg. left holding whip and raising right hand, torch in left field. RPC 4976; SNG Levante, 1586 (8.95 grams / 26 mm) eBay Aug. 2019 $6.00 BO Countermarks: Obverse: Nike advancing left, [holding wreath], in oval (?) (6 x 7 mm). Howgego 258 or 260 (?). "Nike appeared as a type on coins of Macrinus...refer to his Victoria Parthica" (Howgego) Reverse: T in irregular punch. Howgego 686.
That countermark on the left facing Claudius AE Asses appears to be Hercules/ Herakles. (There's one on an Agrippa As in the current HJB sale, BBS 219, 357.) It's cited as Martini-Pangerl 99 in Andreas Pangerl's Museum of Roman Countermarks, which they attribute to the Danube region. Haven't checked Howgego or Werz, wouldn't surprise me if it's in the latter.
Sorry if this is redundant, but for those language-challenged of us who missed the earlier posts about it, make sure to check out Google Translate. You can take a picture of a foreign language pdf on your computer screen and see the translation in seconds. It took me less than a minute to translate the introductory page in Werz from the links provided. Not perfect by any means, but good enough. Foreword The present work is the text of my dissertation, which has been slightly changed and partially streamlined, and which was accepted in April 2001 by Department 08 of the Johann Wolfgang Goethe University in Frankfurt am Main. The aim of the work is to present an easy-to-use catalog of early Imperial coins with countermarks from the Rhine area. A citation work is to be created through a systematic recording and treatment of the countermarks, which will help to record the circulation of coins in the Rhine area more precisely than was previously possible. Literature published after 2001 could only be included in a few cases. In recent years, a number of publications on counterstamped coins from the Roman Empire have appeared. However, they only rarely allow conclusions to be drawn about coin circulation in the Rhine area. Incorporating these publications later would have enlarged the catalogue, but hardly the knowledge gained". On the other hand, an attempt was made as far as possible to take into account the more recent coin finds and coin find publications. The work was supervised by my supervisor Prof. Dr. HM. suggested by Kaenel. I owe him a lot. Prof. em. dr M. R.-Alföldi and employees of the Ancient Coins Project (FdA) were willing to discuss and thus made it possible to solve many of my questions. J. Starck MA did the difficult work of the first proofreading. His effort and patience were of great value. Financially, the work was funded over a period of two years by the graduate scholarship to För Development of young scientists from the Johann Wolfgang Goethe University in Frankfurt am supported. The independent processing of the countermarked coins from Martberg Pomerania, for which FMRD volume IV.4.1, which is about to be created, also produced a small helpful amount of money. My colleagues in the coin cabinet of the city of Winterthur lic. phil. Benedict Zäch, Inge Ghelfi and lic. phil. I am deeply indebted to Luisa Bertolaccini MAS. supported you me lovingly and helpfully not only in the lengthy and not always easy Printing. Parts of the manuscript read lic. phil. Luisa Bertolaccini MAS (Winterthur and Baden), Dr. Susanne Frey-Kupper (Prahins), Dr. Peter Ilisch (Muenster), Dr. Stefan Krmnicek (Frankfurt am Main), Dr. Markus Peter (Augst). Prof. Dr. Michael A. Speidel (Basel) and lic. phil. Benedikt Zäch (Winterthur). They all contributed valuable suggestions with their help and made me goofy inaccuracies attentive.