Arimaspi and griffins remained stock images associated with the outlands of the north: the Aeschylan "Prometheus Bound" (ca 415 BC?), describing the wanderings of Io, notes that she is not to pass through the north, among the Arimaspi and griffins, but southward. Herodotus, "Father of History", admits the fantastic allure of the edges of the known world: "The most outlying lands, though, as they enclose and wholly surround all the rest of the world, are likely to have those things which we think the finest and the rarest." ("Histories" iii.116.1) Ignoring the scepticism of Herodotus, Strabo and Pliny's "Natural History" perpetuated the fables about the northern people who had a single eye in the center of their foreheads and engaged in stealing gold from the griffins, causing disagreements between the two groups.