Answer by Samantha Blankenship
This is a fantastic question. I like to think about this in terms of different networks of information flowing through Persia: some official, others not so official.
The official Achaemenid Persian propaganda machine was truly incredible; in fact, the Great Kings of Persia tell us explicitly that spreading their ideological message to all parts of the empire was a priority. In a long text along with a relief scuplture carved into the cliff face of a sacred mountain (Mount Bisotun in Iran) overlooking an important thoroughfare — a text carved three times in three separate languages — Darius I ‘the Great’ (r. 522-484 BCE) provides a monumental justification for what in reality amounted to his usurpation of the Persian throne. Towards the end of this inscription (at §60), Darius enjoins audiences to ‘declare it [the recorded story] to the people’, and even describes (in §70 of the Old Persian-language version) how he had the text copied on tablets and skins (i.e. parchment) and distributed throughout the empire, ‘everywhere in the lands/peoples’. We know he actually succeeded in disseminating his message widely, because local versions have been found in situ in Babylon and on parchment (in Aramaic translation) at the Jewish garrison in Elephantine, Egypt.
These mechanisms of dissemination were clearly supplemented by oral storytelling as well; this process, and its relationship to the written text at Mt. Bisotun, has been analysed by M. Rahim Shayegan in his book-length study Aspects of History and Epic in Ancient Iran: From Gaumāta to Wahnām (Washington, DC, 2012). Part of the imperial propaganda programme is its translatability into multiple languages (as suggested already by the three different languages in which Darius had the Bisotun Inscription carved); and that explains how the narrative could take on even more linguistic forms and variations as it spread to all parts of the empire, including the Greek- and Carian-speaking margins where Herodotus hailed from.
In my view, though, something equally amazing about Herodotus is that, in addition to knowing what the Persian kings wanted the whole world to know, he also problematizes their official ideological claims. That is, he recognized some discrepancies between the official line and the reality on the ground (see for example Darius’ mercenary attitude to dishonesty at Histories 3.72.4, and his commissioning of a disingenuous trick from his groomsman Oebares at 3.85-87, in contrast to the historical Darius’ insistence on his own truthfulness at DB §§57 and 63). Faced with such disparities, he was able to think about and really critique the limitations on the Persian kings’ ability to control the flow of information throughout their empire and the world beyond. But how exactly would someone like Herodotus know about situations where the official story promulgated by the Great Kings differed from less-flattering realities?
I often think of the passage from the Histories (9.16) in which elite Persians and Greeks recline on couches together at a banquet in Thebes and worry in very personal terms about the human costs of the Greco-Persian War. Herodotus mentions that the story of this banquet was described to him second-hand by a certain Thesander of Orchomenos, who attended the banquet. One pictures Greeks like Herodotus – born a citizen of the Persian Empire when it stretched as far as Halicarnassus – or Thersander, a citizen of a ‘Medizing’ (that is, Persian-allied) city-state, conversing with well-informed Persians at such elite gatherings. Such Persians would have been kept abreast of real conditions very quickly, through official (but not public-facing) channels; the Achaemenids maintained a remarkably swift courier system along the Royal Road system, which Herodotus knew about (Histories 8.98; see also 5.52-53). Even so far away from home, then, Persians assigned to military and political posts in Greek-speaking provinces would be aware of contemporary affairs and could have communicated their own impressions and reactions to interlocutors like Herodotus. By comparing information received through these unofficial channels with the authorized imagery and storylines of Achaemenid kingship, then, Herodotus was able to develop a sophisticated understanding of the relationships between political power and official historical narratives.
Herodotus Helpline 