Egypt, Alexandria. Diocletian 284-305. Tetradrachm. (Bronze, 19.24 mm, 7.05 g). No date but AD 298. “Not issued” series. ΔIOKΛHTIANOC CЄB Laureate, draped and cuirassed bust right. Rev. IC -IC Tyche standing left, wearing crown, chiton and peplos, holding sistrum in her right hand and sceptre in her left. Dattari -. Emmett 4090 (one specimen cited). See Vagi II, pp. 566-9. Choice jade green patina, Near Extremely Fine. Ex Triton VI, New York, Auction 14-15.01.2003, lot 605. Having invaded Egypt in July 297 AD, besieged and conquered Alexandria in April 298 AD, Diocletian took over the mint again and in a very short time (June-October 298 AD) thought about restoring the autonomous Alexandrian monetary system by minting an experimental series of undated bronze coins with the portraits of the Augusti (Diocletian and Maximian) and on the reverse the bust of Serapis-Soter (for the supposed "octodrachms") or the standing figure of Isis-Tyche with sistrum and sceptre (for the alleged "tetradrachms" and "diddrachms"). They are all very rare coins, usually found in splendid condition because they apparently were not circulated, engraved and minted with particular care, with a rather Roman-centric style and careful iconographic research. I defined them as “not issued” series because they are experimental and were not put in circulation indeed (see my quoted paper “Testimonianze sulla fine della monetazione autonoma alessandrina, 296-298 d. C." and bibliography). In fact, it would be an ephemeral project on the part of the Tetrarchs, managed in any case by the Prefect of Egypt who was the Viceroy, perhaps intended as an action as part of a reconciliation announced by Diocletian after the retaking of Alexandria, a project immediately abandoned because it was unsuited for the policy of union and irreversible globalization passed by the Tetrarchy. Our specimen, in this case defined as a "tetradrachm", is fully part of this series as a specimen of great quality and conservation, with a magnificent original emerald patina that uniformly covers the coin. This series chronologically concludes the issues of the glorious autonomous Alexandrian coinage (30 BC -298 AD).