Herodotus[849] notes that among the Libyan tribe of the Nasamones tombs were used for two purposes, for the taking of oaths and for dream oracles. ‘In their oaths and in the art of divination they observe the following practice: they take oaths by those among them who are accounted to be most virtuous and excellent, by touching their tombs, and when they divine they regularly resort to the monuments of their ancestors, and having made supplication they go to sleep, and whatever vision they behold of that they make use.’ Herodotus like many travellers was more familiar, it would seem, with the customs of foreigners than with those of his own people. He notes the two customs as though they were alien curiosities, but the practice of swearing on a tomb must have been familiar to the Greeks. The slave in the _Choephori_ says to Electra[850]: ‘Reverencing thy father’s tomb like to an altar, Mine inmost thoughts I speak, doing thy hest.’ By the hero Sosipolis at Olympia[851] oaths were taken ‘on the greatest occasions’—by Sosipolis who in true hero-fashion was wont to appear in snake-form. That these oaths were taken on his actual tomb we are not told, but the sanctuary of a snake-hero can scarcely in its origin have been other than his tomb. Almost every hero in Greece had his dream oracle. Later as the hero was conceived of as in human rather than animal shape the connection between hero and snake is loosened, and we get the halting, confused theology of Aeneas[852]: ‘Doubtful if he should deem the gliding snake The genius of the place, or if it were His father’s ministrant.’ In fig. 100 we have an altar to a hero found in Lesbos[853], not the old primitive grave mound which was the true original form, but a late decorative structure such as might have served an Olympian. It is inscribed in letters of Roman date, ‘The people to Aristandros the hero, son of Cleotimos,’ and that the service is to a hero is further emphasized by the snakes sculptured on the top round the hollow cup which served for libations. There are two snakes; it is no longer realized that the hero himself is a snake, but the snake reminiscence clings. [Illustration: FIG. 100.] * * * * *