Obol

Comment from Roma Numismatics: "The unique Berlin hemiobol illustrated in Svoronos pl. XXV, 6 provides the link between the tripod obols and the ram's head trihemiobols and confirms the Delphic identity of this type. The reverse of this coin has been variously said to depict a phiale (Svoronos), an omphalos (BMC), and also a wheel, however its significance must be closely connected to the Delphic tripod on the obverse, making its attribution as the omphalos of Delphi the most likely. According to Greek mythology, Zeus sent out two eagles to fly across the world to meet at its centre, the 'navel' of the world. Omphalos stones used to denote this point were erected in several places, but the most famous of those was at the oracular temple of Apollo in Delphi; most accounts place it in the adyton of the temple near the Pythia. The Omphalos at Delphi came to be identified as the stone which Rhea wrapped in swaddling clothes, pretending it was Zeus. This was to deceive Kronos, his father, who swallowed his children so they could not grow up and depose him as he had deposed his own father, Ouranos. The omphalos was thus important in establishing a 'proof of creation' for the Greeks, giving them something to identify with as a race."