Olympia before the Games: the oracle of Zeus and the Iamid seers
The oracle of Zeus at Olympia: the ash altar, divination by sacrificial victims, the Iamid and Clytiad seers and Tisamenus, the soothsayer of Plataea.
Olympia is remembered above all for the Games, but for the ancients it was also a place of prophecy. Strabo observes that the sanctuary's glory had arisen from the oracle of Olympian Zeus and that, when the oracle lost importance, the fame of the place endured thanks to the festival and the temple. At Olympia there were no Pythias and no speaking oaks: the god revealed himself through the fire of sacrifices, read by hereditary families of seers.
The ash altar
The centre of the cult was the great altar of Zeus, which Pausanias describes in detail. It was not built of stone but formed from the ash of the thighs of victims burned in honour of the god, accumulated over the centuries until it reached a considerable height. Every year, according to Pausanias, the ash from the prytaneion was mixed with water from the Alpheus and spread over the altar, which thus slowly grew.
On this altar divination was practised by means of the victims. The seers observed the way the flesh burned, the flame and other signs, drawing from them indications of Zeus's favour. Herodotus, speaking of the Theban sanctuary of Ismenian Apollo, notes that there the god was consulted through victims as at Olympia, a sign that the Olympic method was well known and recognisable.
The families of seers
Prophecy was entrusted to two families: the Iamidae and the Clytiadae. The Iamidae claimed descent from Iamus, son of Apollo and Evadne. Pindar, in the sixth Olympian ode, tells how his mother gave birth to him in secret and left him among violets, where two serpents fed him with honey. When he grew up, Iamus went down into the Alpheus and called on his father, who granted him the gift of prophecy and led him to Olympia.
The same ode is dedicated to Hagesias of Syracuse, victor in the mule-cart race and a member of the Iamid family, a sign that the clan had spread well beyond Elis. The Olympic seers, in fact, did not remain shut in the sanctuary: they were hired by cities and generals to accompany military expeditions and interpret the sacrifices before battle.
Tisamenus and the victory of Plataea
The most famous of the Iamidae was Tisamenus of Elis. Herodotus relates that, after receiving at Delphi a reply saying he would win five great contests, he took up athletics, believing the oracle referred to games. The Spartans understood instead that it meant wars and wanted him on their side. In return Tisamenus demanded Spartan citizenship, an extremely rare privilege, and in the end obtained it for his brother as well.
It was he who interpreted the sacrifices for the Greeks at the battle of Plataea in 479 BC, which ended the Persian invasion. According to Herodotus his five victories were Plataea and four other battles fought by Sparta. The story shows how much weight a seer's word could carry in military decisions.
The Olympic oracle reveals a face of Greek divination different from the Delphic one: no ecstasy or inspired verses, but the careful observation of a rite, entrusted to experts who handed down their knowledge from father to son. Alongside the athletes and the judges of the Games, the Iamidae were for centuries the guardians of this tradition.