C'est malheureusement un faux moulé pour touriste...
Elle est référencée dans la rubrique Fake du forum Ancient Coins.
Description en anglais :
40 MM medallion of Antoninus Pius, probably 19th Century tourist copy.
IMP CAES T AEL ANTONINVS AVG PIVS, laureate head left / PONT MAX, Antoninus Pius on horseback pacing right, raising right hand.
Possibly based on (but mirror-image reproduced) RIC 879 and 890 (pacing left, bust right with PP at end of obv. legend). Appears to have been struck (not cast) with only faint traces of a seam around the edge.