(M60) Both at Thebes and at Delphi the dragon guarded a spring,(204) the water of which was probably deemed oracular. At Delphi the sacred spring may have been either Cassotis or the more famed Castaly, which issues from a narrow gorge, shut in by rocky walls of tremendous height, a little to the east of Apollo’s temple. The waters of both were thought to be endowed with prophetic power.(205) Probably, too, the monster was supposed to keep watch and ward over the sacred laurel, from which the victor in the combat wreathed his brows; for in vase-paintings the Theban dragon appears coiled beside the holy tree,(206) and Euripides describes the Delphic dragon as covered by a leafy laurel.(207) At all oracular seats of Apollo his priestess drank of the sacred spring and chewed the sacred laurel before she prophesied.(208) Thus it would seem that the dragon, which at Delphi is expressly said to have been the guardian of the oracle,(209) had in its custody both the instruments of divination, the holy tree and the holy water. We are reminded of the dragon or serpent, slain by Hercules, which guarded the golden apples of the Hesperides in the happy garden.(210) But at Delphi the oldest sacred tree appears, as Mr. A. B. Cook has pointed out,(211) to have been not a laurel but an oak. For we are told that originally the victors in the Pythian games at Delphi wore crowns of oak leaves, since the laurel had not yet been created.(212) Now, like the Festival of Crowning, the Pythian games were instituted to commemorate the slaughter of the dragon;(213) like it they were originally held every eighth year;(214) the two festivals were celebrated nearly at the same time of the year;(215) and the representative of Apollo in the one and the victors in the other were adorned with crowns made from the same sacred laurel.(216) In short, the two festivals appear to have been in origin substantially identical; the distinction between them may have arisen when the Delphians decided to hold the Pythian games every fourth, instead of every eighth year.(217) We may fairly suppose, therefore, that the leaf-crowned victors in the Pythian games, like the laurel-wreathed boy in the Festival of Crowning, formerly acted the part of the god himself. But if in the beginning these actors in the sacred drama wore wreaths of oak instead of laurel, it seems to follow that the deity whom they personated was the oak-god Zeus rather than the laurel-god Apollo; from which again we may infer that Delphi was a sanctuary of Zeus and the oak before it became the shrine of Apollo and the laurel.(218)