The Arimaspians first entered Greek knowledge through the voice of Aristeas of Proconnesus, a poet from a small island in the Sea of Marmara near the mouth of the Black Sea. Aristeas claimed to have travelled far to the northeast under the inspiration of Apollo, the god of poetry and prophecy, in a trance that left his body behind while his spirit wandered. He reached the land of the Issedones, a people who lived beyond the Scythians in the interior of Central Asia, and from them he learned of the peoples still further north. The Issedones told him of the one-eyed Arimaspians who lived beyond them, and beyond the Arimaspians the griffins that guarded gold, and beyond the griffins the Hyperboreans, whose territory reached to the sea. Aristeas wrote all this down in a poem called the Arimaspeia, a work that is now lost but whose fragments were quoted by Herodotus and other ancient writers with enough fidelity that the outline of the tradition survives.

Herodotus, the Greek historian who wrote in the fifth century BCE and who is called the father of history, transmitted the Arimaspeia tradition in the fourth book of his Histories, his great account of the Scythian world. He placed the peoples in a geographic chain that stretched from the known to the unknown: the Greeks, then the Scythians on the Pontic steppe, then the Issedones further inland, then the Arimaspians, then the griffins, and finally the Hyperboreans at the extreme edge. Herodotus added a crucial detail: the Arimaspians were not merely exotic neighbours but a force of displacement. The Issedones had been pushed from their lands by the Arimaspians, and the Scythians had been pushed by the Issedones, and the Cimmerians by the Scythians, creating a domino effect of migration that rippled across the entire Eurasian steppe. The Arimaspians' aggression against the griffins was not an isolated conflict but the engine that destabilised the whole northern world.

But Herodotus was skeptical. In the third book of his Histories he wrote that the northern parts of Europe had the most gold, and that it was said the one-eyed Arimaspians stole it from the griffins. Then he added, in a sentence that has echoed for two and a half thousand years: "I do not believe that there are men born with one eye who are in other respects like other men." He transmitted the story faithfully, as he always did, but he would not vouch for it. The one eye was too much. The griffins were too much. The whole tradition belonged to the edge of the world, where the light of reliable knowledge grew dim and the imagination took over.

The Arimaspians themselves were described as fierce, horse-riding warriors, rich in livestock, covered in shaggy hair, and of very noble character despite their warlike nature. Their single eye was not a disability but a defining mark, set in the centre of the forehead like the Cyclopes of Homer's Odyssey, though the Arimaspians were mortal men and the Cyclopes were giants. They rode horses across the steppe, attacked in swift raids, and carried weapons of bronze and iron. Some later writers, seeking to explain the one eye, suggested that the Arimaspians wore helmets with narrow visors, or that the description was a misunderstanding of some facial marking or tattoo. Modern scholars have proposed that they reflect distorted Greek knowledge of actual Central Asian nomadic peoples, possibly the Alans or early Hunnic groups, whose gold-rich territories in the Altai Mountains may have given rise to the tradition of guarded treasure.

The griffins they fought were not the decorative heraldic beasts of later European art. They were fierce, lion-bodied, eagle-headed creatures that nested in the mountains above the gold deposits and defended them with absolute ferocity. Aeschylus, the tragedian who wrote in the fifth century BCE, called them "the sharp-beaked hounds of Zeus that bark not" in his play Prometheus Bound, where the Titan warns the wandering maiden Io to beware both the griffins and the one-eyed Arimaspians who dwell about "the flood of Pluto's stream that flows with gold." The griffins were not merely animals. They were agents of divine protection, guardians of a sacred substance that belonged to the gods or to Apollo himself. The gold they guarded was not ordinary wealth but something that carried the divine touch, a trace of the sacred in the mortal world.

The war itself had no beginning and no end. It was perpetual, a permanent condition of the northern frontier. The Arimaspians raided by night, when the griffins patrolled less effectively, and attacked in large organised parties rather than as individuals. The griffins defended their nests and their gold with the ferocity of creatures that knew no fear. Aelian, the Roman writer on animals, described the griffins as laying eggs that resembled agates and noted that only elephants and dragons could withstand them. Pliny the Elder placed the Arimaspians near the cave of the north wind, the Earth's Door-Bolt, and described their war with the griffins as a continual struggle over gold dug from mines. Pausanias, the Greek traveller, reported that griffins were depicted on Athena's throne on the Athenian Acropolis, fighting the Arimaspians for gold beyond the Issedones.

The Arimaspi-Griffin war was depicted in Greek art as early as the fifth century BCE. Red-figure vase paintings show Arimaspians on horseback, wearing Scythian tunics and leggings, confronting rearing griffins with wings spread and beaks open. The scenes were dynamic and violent, a visual tradition that circulated independently of the literary sources and may preserve details that the texts do not record. The image of the one-eyed rider and the winged guardian became an enduring motif in Western art, passing from Greek pottery through Roman mosaics to the decorative borders of medieval maps, where griffins still guard the edges of the known world.