Here are presented the results of the enquiry carried out by Herodotus of Halicarnassus. The purpose is to prevent the traces of human events from being erased by time, and to preserve the fame of the important and remarkable achievements produced by both Greeks and non-Greeks; among the matters covered is, in particular, the cause of the hostilities between Greeks and non-Greeks.— Herodotus, The Histories
Robin Waterfield translation (2008)
Discoveries made since the end of the 19th century have generally added to Herodotus's credibility. He described Gelonus, located in Scythia, as a city thousands of times larger than Troy; this was widely disbelieved until it was rediscovered in 1975. The archaeological study of the now-submerged ancient Egyptian city of Heracleion and the recovery of the so-called "Naucratis stela" give credibility to Herodotus's previously unsupported claim that Heracleion was founded during the Egyptian New Kingdom.
Modern scholars generally turn to Herodotus's own writing for reliable information about his life, supplemented with ancient yet much later sources, such as the Byzantine Suda, an 11th century encyclopaedia which possibly took its information from traditional accounts.
Herodotus is neither a mere gatherer of data nor a simple Teller of tales – he is both. While Herodotus is certainly concerned with giving accurate accounts of events, this does not preclude for him the insertion of powerful mythological elements into his narrative, elements which will aid him in expressing the truth of matters under his study. Thus to understand what Herodotus is doing in the Histories, we must not impose strict demarcations between the man as mythologist and the man as Historian, or between the work as myth and the work as history. As James Romm has written, Herodotus worked under a Common ancient Greek cultural assumption that the way events are remembered and retold (e.g. in myths or legends) produces a valid kind of understanding, even when this retelling is not entirely factual. For Herodotus, then, it takes both myth and history to produce truthful understanding.