It is a tridarchm of Trajan, Cappadocia-Caesarea, with Zeus on the reverse. It is the first coin of this fairly unusual denomination that I have owned, and the reverse is most intriguing. Here's what Beast Coins has to say about it: "This remarkable silver tridrachm type belonging to the opening phase of Trajan's reign has been the subject of considerable scholarly debate. Traditionally, it was assigned to Caesarea in Cappadocia (BMC and Sydenham) but in 1977 D. R. Walker reattributed it to an unidentified mint in Provincia Asia on the basis of its absence from any of the finds of Caesarean coinage. This reassignment was accepted by Metcalf in his 1996 publication on the silver coinage of Cappadocia from which the type was excluded. However, the reverse design has a distinctly oriental flavor and a further reattribution may be necessary at some future date. Update from Richard McAlee on April 2, 2008: This type has now been reattributed to Syria-Phoenicia as far as area of circulation, but it was actually minted in Rome for use in Syria-Phoenicia. See the chapter on Trajan's coins in my new book, "The Coins of Roman Antioch". The coin posted here is a pleasing example, fairly well centered, but lightly cleaned. Roman Empire, 98-99 AD Trajan Tridrachm Cappadocia-Caesarea (possibly minted in Rome - see note above) Obverse: Laureate head of Trajan right. Reverse: Zeus facing right, with thunderbolt in left hand, and mappa or short scepter in right, DHMARX EX-UPAT B in legend. 9.9 grams 21 mm, 6 h. BMC Cappadocia p. 52 and 46; Sydenham (The Coinage of Caesarea in Cappadocia) 173; cf. Metcalf (The Silver Coinage of Cappadocia, Vespasian-Commodus) p. 148; cf. Walker (The Metrology of the Roman Silver Coinage, part 2), p. 99. Very scarce. .