The period of the Persian Wars is also the beginning of written history with the work of Herodotus, the primary source for information about the wars. The Persian Wars took place in the sixth and fifth centuries B.C. The history of Herodotus consists of nine books, a structure created not by Herodotus but by a later editor. The work falls into three major sections, each consisting of three parts. The first section comprises the reigns of Cyrus and Cambyses and the accession of Darius. The second tells of the reign of Darius. The third covers that of Xerxes. Herodotus offers an assessment of the origins of the enmity between the Greeks and the Persians and gives some insight into the question of how the wars developed, an issue that continues to be of some controversy given the fact that the reasons for the beginning of the Persian Wars remains obscure.
The history of the various wars is known and covers a period of over a century. Darius came to power in Persia by being the strongest general in the army of Cambyses, and he crushed the rebellion that followed the death of that ruler and became ruler himself. By 521 B.C., Darius had restored peace. He then undertook a program of imperial expansion, and in 516 he moved across the Hellespont in a campaign against the Scythians. He was forced to retreat, but he had established a bridgehead in Europe. A revolt in Ionia in 500 B.C. halted expansion temporarily. Athens assisted the rebels in 498 B.C. so that the Greeks could take the offensive. The Persians by 494 B.C. were able to fight back with a program of suppressing local tyrants. From a base in recovered Thrace and Macedonia, Darius invaded Greece proper in 492 B.C., but he met defeat at Marathon in 490 B.C. Darius believed that a more coordinated attack could succeed, but he died before he could put such a plan into effect. Xerxes followed his father, crushed the rebellion then taking place in Egypt, and set himse...