For a great deal of ancient religion Herodotus is not the best witness but the only one. Persian practice without images, temples or altars, with sacrifice on a high place and a magus chanting a theogony over the victim, comes from him. So does Scythian burial, the killing of horses and attendants, the mound raised over the king, and the vapour bath in which hemp seed is thrown on hot stones inside a felt tent while the mourners howl with pleasure. So do whole layers of Egyptian practice, the grades of mummification and their prices, the animal cults, the festival crowds on the Nile, the prohibitions and purities of the priests.
Some of it has been confirmed since. Excavated Scythian burial mounds have produced the horse sacrifices, the tent frames and the hemp, in an arrangement close enough to his description to be striking. Other parts have not been confirmed and probably cannot be. He has been called the father of history and the father of lies since antiquity, and the honest position is that he is a reporter of what people said about themselves, which is a different and often more useful thing than a record of what they did. Reading him requires keeping both facts in mind at once, and the atlas cites him on that understanding.