Nor is it Ion only who knows that this place was honoured by the Pythian fires, it is no mere ‘poetical’ figure. Strabo[153], in speaking of a place called _Harma_ in Boeotia, says we must not confuse this Harma with another Harma near Pyle, a deme in Attica bordering on Tanagra. In connection with this Attic Harma, he adds, the proverb originated ‘When it has lightened through Harma.’ Strabo further goes on to say that this Harma, which is on Mt Parnes, to the North-West of Athens, was watched by certain officials called Pythiasts for three days and nights in each of three successive months; when a flash of lightning was observed a sacrifice was despatched to Delphi. The place whence the observation was taken was the altar of Zeus Astrapaios, Zeus of the Lightning, and this altar was _in (or on) the (Acropolis) wall between the Pythion and the Olympion_. Euripides, it is clear, is alluding to this definite ritual which of course would be familiar to Ion. That ritual he clearly conceived of as taking place near the Long Rocks. Near the Long Rocks must therefore have stood the altar of Zeus of the Lightning, on the wall between the Olympieion and the Pythion. Not only the Pythion but the Olympieion must therefore have been close to the Long Rocks. The word used by Strabo for _wall_ (τεῖχος) is strictly a fortification wall, and we should naturally understand it of that portion of the Pelargikon which defends the North-West corner of the citadel and abuts on the Long Rocks (Fig. 2). It is just here, close to the Pelargikon that we should, from the account of Pausanias[154], expect to find Apollo’s ‘best loved’ sanctuary. Pausanias on leaving the Acropolis notes the Pelargikon, or as he calls it Pelasgikon, and immediately after says ‘on the descent not to the lower parts of the city but just below the Propylaea, is a spring of water, and close by a sanctuary of Apollo in a cave; they think that it was here he met Creousa, the daughter of Erechtheus.’