It was no small enterprise upon which the mind of Cyrus was now bent, and at first sight it might well have been pronounced altogether hopeless. How could a mere governor of a province hope to unseat from his throne the Great King with all the resources of the empire at his command? At the most, Cyrus could only reckon upon some 100,000 soldiers, whereas Artaxerxes was able to bring more than a million of men into the field.
On the other hand however, it might be urged that the Great King could not at once assemble his whole force. So immense were the distances in this huge empire, that a whole year of preparation would be required, in order to bring up the army to its full strength. And Cyrus intended, if possible, to take his brother by surprise. He believed moreover that his disadvantage in point of numbers would be more than counterbalanced by the infinitely superior quality of at least a part of his army.
It was from among the Hellenes that he hoped to enlist such troops as could not fail to ensure his success. Some years before this, he had visited Hellas as his father's ambassador at the time of the Peloponnesian war, and had observed the unusual talent displayed by the Hellenes for military enterprise. He had made many friends among them, whose friendship he still retained, and he was anxious to induce as many Hellene soldiers as possible to enter his service.
The Hellenes had always been fond or adventure, and just at this time there were numbers of them willing and eager to engage themselves to a foreign master who promised good wages, especially when this master was a prince well known to be generous and open-handed, and above all, a lover of Hellas and the Hellenes. During the long Peloponnesian war they had become accustomed to an unsettled, adventurous camp-life, and now that the war was over, they did not care to return to peaceful pursuits.
But Cyrus could not, without betraying his plans, begin openly to enlist foreign troops. It was necessary to find a pretext for employing them, and in this he was helped by fortune. For several hundred years there had been established along the west coast of Asia, numerous flourishing colonies of Ionian Hellenes. At first, and for a long time, they were free states, but they had been conquered at last by the Persians, and now they formed part of the Persian empire, and were included in the satrapy of Tissaphernes.
Most fortunately however for Cyrus it happened that just at this time the Ionian cities rebelled, not against the Great King, but against Tissaphernes, and begged Cyrus to take them under his protection. To this he gladly agreed, for it gave him a pretext for declaring war against Tissaphernes, and supplied a cloak with which to cover the preparations he was making for his great enterprise. Accordingly he sent word to the Ionian cities that their garrisons should be strengthened by the addition of Hellene soldiers, which he proceeded to levy for the purpose. He also raised troops for the relief of Miletus, one of the largest of the cities, and the only one left in the hands of Tissaphernes, who had received the news of the intended revolt in time to enable him to take prompt measures for suppressing it. He had removed the garrison, put to death the leaders of the opposition, and banished all suspected persons. These banished inhabitants had come to Cyrus, and in answer to their entreaties, he agreed to besiege Miletus both by land and water.
It may seem strange that, one satrap should have been able to wage war against another, whilst all the time both continued to be subjects of the Great King. But in point of fact, such rivalries between neighbouring satraps were rather encouraged than otherwise by the Great Kings, who lived in constant fear lest one or other of the great lords should take it into his head to make himself an independent sovereign, and consequently felt more secure when they were occupied in quarrelling among themselves. In this case moreover, the royal revenue suffered no loss through the revolt of the Ionian cities, for Cyrus took care to forward the tribute which they were required to send to Susa, just as regularly as it had before been sent by Tissaphernes.
Other opportunities also offered themselves to Cyrus for increasing the number of Hellene soldiers in his pay. About this time he received a visit from a Spartan named Clearchus, whose acquaintance he had made during the Peloponnesian war, and of whose ability as a military commander he had the highest opinion. Clearchus had come to him with a request on behalf of the cities of the Hellespont, who were at war with their barbarous neighbours, the Thracians, and could not hold their own against them without help. He wished to aid his countrymen by raising an army for their defence, and asked Cyrus to grant him for this purpose a sum of 10,000 darics. The request was a large one, but it was at once granted by Cyrus.
Shortly afterwards there came to him a Hellene from Thessaly, with a similar request. In his country, the party of which he was leader found itself hard pushed by the opposing faction, and he also desired to raise an army by means of which he and his friends might again have the upper hand. He asked Cyrus to let him have as much money as would enable him to hire 2,000 men for three months. "I will give you gold enough," said Cyrus, "to hire 4,000 men for six months, on condition that you prolong the quarrel with your enemies until I send for you."
Other requests of a similar kind were also granted by Cyrus, always with an intimation that he might require the troops later on for his own service. And thus he secretly collected a force of Hellenes which he kept employed in other undertakings, but ready to come to him when he should want them.
Meanwhile he was careful not to neglect any means of improving the Barbarian soldiers of his provinces, and this could be done openly, for it was part of his duty as satrap to practise the troops in all kinds of military exercises calculated to increase their efficiency.
All this time the Great King was constantly sending spies to Sardis to find out what his brother was doing, but on their return the spies invariably reported that they had seen nothing that could be regarded as suspicious. The fact was that Cyrus knew so well how to make himself agreeable to the spies, that although they reached Sardis as the friends of the King, they always became, before leaving it, the friends of Cyrus.
Every step that he took was weighed by Cyrus with the utmost caution; every difficulty that was likely to present itself on the road to Susa was considered carefully and deliberately, in order to ascertain the best means of overcoming it. No feeling of impatience was allowed to urge him on to any rash or premature action.
At last, three years after his return from the court, he judged that the preparations were sufficiently advanced, and that the time had come when he might venture to call in the companies of Hellene mercenaries from their various services, and also assemble his Persian troops.
Even now however he took care not to disclose the real object of the campaign. For had he announced his intention of marching against Susa, the Great King would have been at once put upon his guard, and moreover he had every reason to fear that the Hellenes would refuse to enter upon the expedition, if they knew how desperate was the venture, and how far it would lead them from their homes. By means of his posts the King could hear in less than a week of what was doing at Sardis, but an army could not march from thence to Susa in less than six months.
For these reasons Cyrus announced that the expedition was to be directed against the marauding tribes of Pisidia, who had often made raids upon the neighbouring provinces, and laid them waste. These tribes must, he said, be exterminated, in order to maintain the safety of the empire.
But there was one whose sharp eyes had followed all the doings of Cyrus with the close watchfulness of hatred, and who saw clearly through the veil with which he sought to conceal his real purpose. This was his neighbour, Tissaphernes. When he heard of the great host gathered together for the expedition against the Pisidians, Tissaphernes felt certain that Cyrus was aiming at nothing short of the throne of Persia; and taking with him a troop of five hundred cavalry, he set off at full speed for Susa, that he might be the first to warn the King of the approaching danger.