The scope of the Histories, covering anthropology and geography, early origins and the grand narrative of Greek-barbarian relations culminating in the Persian Wars, is not to be found in any writer we know of before Herodotus. The story of the Persian Wars themselves has been called 'the greatest continuous prose narrative in Greek literature, and a literary masterpiece', but of course the Histories is more than a narrative, encompassing descriptions of virtually all the peoples of the known world. The Iliad and Odyssey could provide a model for narrative history, and remained the measure against which Herodotus and Thucydides set their histories. Herodotus opens with a promise to tell of the 'great and wondrous deeds' both of Greeks and of barbarians, to preserve the past before it gets forgotten, and show the cause (aitie) of the conflict. That aitie encompasses the many facets of the past, even the remote past, which could explain the Greek-barbarian conflict, and the past and present achievements, lands, peoples, customs, on either side.

It is not easy to pin down the antecedents of the Histories, still less the intellectual background. We can see points of contact between the Histories and certain Presocratic natural philosophers of the sixth-century Ionian Enlightenment, and they share a desire to make sense of the world in non-mythical and non-genealogical terms, which we could call 'rational'. Herodotus' contemporary world is also significant. A writer's background involves looking at earlier influences, but this can marginalise the question of interaction with or reaction to his contemporaries.