There were even primitive Ethiopians painted in savage style, whose Stone Age weapons contrasted strangely with the sophisticated armour and swords of the immaculate Persian royal guard. It was the year 480 B.C. and Xerxes had given the order for the invasion of Europe.

The King’s writ had gone forth, and when he himself went to war, every nation, tribe and race within the vast Persian Empire was expected not only to furnish its due contingent of men, but those men must also be led by their own kings, leaders, or princes. All were vassals of the Great King, who had described himself in an inscription at Persepolis: ‘I am Xerxes, the King, King of Kings, King of the lands … son of Darius the king, the Achaemenian; a Persian, son of a Persian, an Aryan, of Aryan stock.’

The eldest son of Darius by the elder daughter of Cyrus, Xerxes was thirty-eight years old. Although the picture of him that was subsequently drawn by Greek historians and dramatists shows us a traditional Oriental tyrant, it is noticeable that Herodotus himself concedes a number of virtues to this arch-enemy of his people. Xerxes, as he depicts him, is capable of compassion as well as of regal munificence. He had, as was natural for a Persian of his rank and breeding, not only a love of the chase but also a rich appreciation of the natural beauties of the world. A deeply religious man, he was a Zoroastrian. While the great achievements of Greece in philosophy, science, and speculation about the nature of the universe largely lay in the future, the amoral Gods of the Homeric world were still dominant in the religious conceptions of most Greeks. Xerxes, however, believed in the inspired message that Zoroaster, the prophet, had left behind many centuries before. What distinguished the religion of the Persians from that of the contemporary Greeks has been summed up by H. Humbach, the translator of verses which are ascribed to Zoroaster:

It is really the knowledge of the directly imminent beginning of the last epoch of the world, in which Good and Evil would be separated from one another, which he gave to mankind. It is the knowledge that it lies in every individual’s head to participate in the extirpation of Falsehood and in the establishing of the kingdom of God, before whom all men devoted to the pastoral life are equal, and so to re-establish the milk-flowing paradise on earth.

An inscription at Persepolis made early in the reign of Xerxes records the ruler’s dedication to his religious faith: ‘A great god is Ahuramazda, who created this earth, who created man, who created peace for man; who made Xerxes king, one king of many, one lord of many.’

Xerxes, as his conduct shows, was prepared to concede that other variants of religious belief were recognised in various guises by other nations. In his conquest of ‘rebellious lands’, primarily Egypt, he had done his best to uproot the polytheism that he had found rampant everywhere. But the one thing that the Greeks, against whom he was now to wage war, could not ever accept was the fact that Xerxes, like all Eastern potentates, claimed for himself the divine right of kings — ‘one lord of many’.

The invasion of Greece, which was about to take place, was in no sense a religious war: such a concept had hardly evolved, except, perhaps, among the Jews, who saw themselves as God’s chosen people destined to bring the light of their knowledge of God to the heathen by whom they were surrounded. No, what the Greeks resented above all - though almost every small area and city-state was at variance with the other - was the assumption that any man could call himself the God-appointed ruler of all other men. What, on the surface, almost united Greece in the struggle that was to follow was the simple survival instinct. The invasion of Greece made the turbulent, brilliant people of this mountainous and largely inhospitable land aware that they shared one thing in common: a belief in the individual human being’s right to dissent, to think his own way, and not to acknowledge any man as a ‘monarch of all I survey’. Curiously enough, the state of Sparta, which was to play a large part in the campaign, was the only one where men had evolved a constitution in which the individual was trained and disciplined to be totally subordinate. The difference was that the Spartans were indeed subject, although not to a ‘Great King’, but to the concept of the State itself. Perhaps Demaratus, the exiled king of Sparta, who actively helped Xerxes in his campaign, put it best: ‘Even though the Spartans are free, still they are not wholly free. The law is their master, and they fear this more than thy people fear thee.’

Xerxes in his great proclamation at Persepolis, after recording how he had put down a rebellion in what one presumes was Egypt, had it inscribed that:

Within these lands there were places where formerly the Daevas had been worshipped. Then by the will of Ahuramazda I uprooted the cult of the Daevas, and made proclamation: The Daevas shall not be worshipped. Where formerly the Daevas had been worshipped, there did I worship Ahuramazda according to Truth and with the proper rite. Much else that was ill done did I make good. All that I did, I did by the will of Ahuramazda. Ahuramazda brought me aid until I finished my work. Thou who shalt come after me, if thou shalt think, ‘May I be happy while alive and blessed when dead,’ have respect for the law which Ahuramazda has established, and worship Ahuramazda according to Truth and with the proper rite.

The false gods (Daevas) whose worship Xerxes had forbidden were, in this case, the vast pantheon of Egypt. It is significant that there are no statues of Xerxes in Egypt. Where the great Darius had been tolerant in his treatment of foreign religious practices, Xerxes would seem to have taken the commands of Zoroaster more literally.