Alexander (2.4-2.5)

Moreover, a serpent was once seen lying stretched out by the side of Olympias as she slept, and we are told that this, more than anything else, dulled the ardour of Philip’s attentions to his wife, so that he no longer came often to sleep by her side, either because he feared that some spells and enchantments might be practised upon him by her, or because he shrank from her embraces in the conviction that she was the partner of a superior being.

But concerning these matters there is another story to this effect: all the women of these parts were addicted to the Orphic rites and the orgies of Dionysus from very ancient times (being called Klodones and Mimallones[*]), and imitated in many ways the practices of the Edonian women and the Thracian women about Mount Haemus, from whom, as it would seem, the word threskeuein [*] came to be applied to the celebration of extravagant and superstitious ceremonies.