Thus personal feeling, political fears, and commercial necessities actuated Crœsus to challenge Persia. With this end in view he formed a series of alliances. Nabonidus of Babylon and Aahmes II of Egypt, menaced like Crœsus himself by the ambition of Cyrus, promised him their aid. Foreseeing a conflict with one or another of the powers of the Orient, Crœsus had some time before assured himself of the help of the greatest military power of the time, Sparta. Now that war was imminent, he sent an embassy which by flattery and the representation that the enterprise had the sanction of the Delphic oracle easily induced the Spartans to sign the compact of alliance and friendship.
After this brilliant diplomatic campaign Crœsus believed success was certain. Lacedæmonia was fitting out vessels and equipping troops. Aahmes despatched his contingent. Nabonidus was only awaiting a signal to take the field; his tributaries, the Phœnicians, were ready to obey. Lydian agents were recruiting mercenaries in Thrace. If the forces of the league could have effected their junction, Cyrus would have found himself in grave peril.
But he was warned in time. An Ephesian whom Crœsus despatched to the Peloponnesus to enlist soldiers deserted to Cyrus and informed him of the coalition that was forming against him. The Persian king hastened to act before his enemies were ready. Babylon being his nearest adversary, he at once attacked the city.
Without waiting for the union of all his forces, without which such an undertaking was quite hopeless, Crœsus hastened to go to the relief of his ally. He crossed the Halys and took the city of Pteria without much difficulty. But he had not counted on the fearful energy of his foe. Cyrus at once set out for the north with his entire army. Passing through the defiles of Cappadocia, he quickly made himself master of the Anti-Taurus, and was in a position from which he could make an attack wherever he chose. Then he proposed a peaceful settlement, offering Crœsus, if he would become a vassal of Persia, the retention of his kingdom with the title and dignity of satrap. The Lydian king defiantly replied that he had never served any one, as had the Persians, the former slaves of the Medes and future slaves of the Lydians.
But these boastful words were not borne out in the campaign that followed. Not only did Crœsus prove himself to possess none of the qualities of a good general, but his heterogeneous army of mercenaries and foreign auxiliaries was utterly unable to cope with the seasoned troops of Cyrus. There was a single furious and bloody battle, which, according to Herodotus, was indecisive, but which other writers, probably with greater accuracy, declare was a victory for the Persians. Crœsus evacuated Pteria, abandoned the bend of the Halys, although it presented an excellent line of defence, and returned to Sardis. He felt quite secure here, for he did not dream that Cyrus would follow at once.
But Cyrus did follow very promptly, after having removed the danger of an attack in the rear by a treaty with Nabonidus. The sudden appearance of the Persians before the gates of Sardis astonished Crœsus, but did not dismay him.
The short campaign which ensued culminated in a great battle on the plain of Thymbrium. (Herodotus says “the plain before Sardis.”) The forces of Crœsus were much depleted by the dispersion of his mercenaries, especially of the Greek hoplites. Of his allies Aahmes was the only one who had sent his contingent. Crœsus’ great hope lay in his famous cavalry, which was considered the bravest and most skilful in the world. Nor were the Persians without fear of these terrible lancers, who might create irremediable disorder should they once succeed in breaking the Persian lines and penetrating the squares of the infantry. To avoid this danger Cyrus employed a stratagem that was suggested by a Mede. He covered the front of his army with a line of camels. Charging upon these enormous beasts that were opposed to them, the Lydian horses were so startled at the sight of them and so annoyed by their odour that they were thrown into confusion and the riders forced to dismount. But in spite of their courage they were overwhelmed and routed by the rude foot-soldiers of Iran. The survivors reached Sardis in safety, and were besieged there by Cyrus.
The defeat of Thymbrium placed Crœsus in a most critical situation. He despatched couriers everywhere, especially to Sparta, to beg his allies for help. The Lacedæmonians, whose soldiers were ready and vessels equipped, were about to give the order to set sail when a new message brought consternation to the city. Sardis had been taken and the king was a captive. [546 B.C.]
Among the conflicting accounts of the fall of Sardis, that of Herodotus appears to be the most trustworthy. According to him the walls were stormed at a vulnerable point that had been discovered accidentally by a Persian soldier.