EGYPT. Ptolemy I Soter
AR tetradrachm, 27 mm, 17.0 gm (Attic standard)
Alexandreia mint, struck 313/12 BCE
Obv: Head of the deified Alexander III to right, wearing mitra of Dionysos and elephant skin headdress, with aegis around his neck, and with horn of Ammon on his forehead
Rev: ΑΛΕΞΑΝΔΡΟΥ; Athena Alkidemos advancing right, hurling spear with her right hand and with shield over her extended left arm; to right, eagle with closed wings standing on thunderbolt to right with ΔΙ below
Ref: Svoronos 33; Zervos series D, issue XIII; SNG Copenhagen 14; BMC 7
From a similar coin in CNG's archives:
The coinage of Ptolemy I developed in a fairly complex way. He first issued normal issues in the name of Alexander, then changed them by inaugurating a new obverse type showing Alexander wearing an elephant’s skin headdress in circa 321. In 314 this was changed by replacing the seated Zeus on the reverse by an archaizing fighting Athena - Athena Alkidemos. These coins were of Attic weight.