PROFESSOR GRUBE has for some years past taught a course of which the Histories of Herodotus formed a part. I hope, therefore, that he will be interested in the problem I wish to raise, since it is a problem for all readers of Herodotus, ancient and modern, who begin to read his Histories as he wrote them from the first book onwards. How did Herodotus construct an intelligible framework for his narrative of the Persian Wars and his account of the antecedents of the protagonists in that struggle, both Greek and barbarian, and in particular why did he begin the detailed narrative where he did, with the reign of the Lydian king Kroisos? Several recent critical studies have been concerned with the first question, and it is fortunately no longer necessary to defend Herodotus against the charge of being incompetent or casual in dealing either with the complexity of his varied materials or with the chronological structure of the Histories.' His data have been checked against external evidence: Oriental primary sources such as Assyrian records, the Nabonidus Chronicle, and the Behistun inscription; eclipses and other such phenomena mentioned by him and now dated by astronomers' calculations; Greek epigraphical sources such as the Athenian archon list, early ostraka, and dedications; archaeological corroboration from, for example, pottery, grave deposits, early buildings and statues, bronzes, ivories, or coins, for such events as the foundation dates of colonies; later chronographers, compilations; and so forth. As a result of this extensive and meticulous re-examination, advances have been made in understanding the chronology particularly of the period from the eighth to the end of