Herodotus, a Greek from Halicarnassus on the coast of what is now Turkey, wrote The Histories in the fifth century BC: an inquiry into why Greeks and Persians fought, and a map of the world that inquiry needed. This is Book 4, called Melpomene. By Book 3, Persia has taken Egypt, a pretender has been cut down, and Darius — who won the crown by a horse’s neigh at dawn — sits as Great King.

Here Darius marches north into Scythia, the grassland above the Black Sea. He finds no cities. The horsemen keep falling back, leaving the land and their fathers’ graves. Their king, Idanthyrsus, sends a bird, a mouse, a frog, and five arrows; Darius reads the riddle too late: you do not own people who will not stand still. Herodotus then maps the rivers that feed the Black Sea, the Issedones, and rumored gold-guarding griffins. In Libya he walks among Cyrene, the Lotus-Eaters, and the Nasamones, who sleep on ancestral tombs to dream. Darius goes home through Thrace with forts on the Danube and little else.