Herodotus devoted much of the first book to the Persians, their conquest of Lydia, and their subjugation of the Greek cities on the coast of Asia Minor and the offshore islands. He spends a great deal of time on the Ionian Revolt, provoked by Persian expansion, because it is both the predecessor and a major cause of the first Persian War with the mainland Greek cities. The early Greeks, who were not unified either in dialect or ethnicity, were divided into distinct ethnic and dialect groups: The Ionians, who were predominant in Asia Minor, the Aegean islands, the great island...