NOT IN RIC
UNLISTED ISSUE. Rev. legend similar to legend on coins minted in Alexandria under Maximinus II (cf. Heesch p. 67, type 6 and 7; see example of Heesch 6a). Apparently, this coin was minted earlier. Not listed in Heesch. Not listed in Vagi. Not listed in Alföldi.
Florian Haymann dates these coins (following Wolfram Weiser) to 297/298 (see: Florian Haymann, Eine neue alexandrinische Lokalbronze des Maximianus Galerius, "Numismatisches NachrichtenBlatt" 4/2022, p. 140). Maybe this date should be shifted to the time of the Great Persecution, i.e. year 303. According to Lactantius, it was started by Diocletian at the instigation of Galerius and all coins known so far are minted only for these two members of the Tetrarchy. Maximinus' emissions with images of the old gods (minted during the persecution in year 312) probably imitated this very issue.
ALEXANDRIA, DIOCLETIAN, UNLISTED ISSUE [DEAE SANCTAE ISIDI]
ALEXANDRIA, GALERIUS MAXIMIAN, UNLISTED ISSUE [DEAE SANCTAE ISIDI]
ALEXANDRIA, GALERIUS MAXIMIAN, UNLISTED ISSUE [DEO SANCT SERAPIDI]