Along the western shore of Asia Minor there were many Greek colonies. One of these was called Ionia, and the chief city of the Ionian state was Miletus.
The Greeks who lived in these colonies owned, often against their will, the King of Persia as their overlord. In time of war they were forced to fight for him.
In 521 b.c. a great monarch, named Darius, became King of Persia. He added many kingdoms to his dominions during the first nine years of his reign. In 512 b.c. he determined to conquer Greece and add it also to his possessions.
So he assembled a great army and crossed the Bosphorus, but instead of going west to Thessaly which lies in the north-east of Greece, Darius turned first toward the north, and crossing the Balkans, he reached the river Danube. Beyond the river lay a wild and desolate country, the home of the Scythians, who wandered up and down the land, settling now here, now there, as their fancy pleased.
The "great king," as the Persian monarchs were often called, bade the Ionian Greeks, who formed part of his army, throw a bridge of boats across the river. When this was done he bade them stay to guard the bridge, while he marched with the main body of his men into the wild Scythian country. Should he not return in sixty days, Darius told the Ionians that they might break up the bridge and go back to their homes.
No sooner had the great king crossed the bridge and marched into Scythia, than his difficulties began.
The foe he had come to seek was not to be found. Knowing that they were not strong enough to face Darius in battle, the Scythians had driven their herds far into the desert, while they themselves, like shadows, dogged the steps of the Persian army.
Two months passed, and still the king had not been able to make the enemy fight. Their shadowy forms were sometimes seen, but they were never near enough to be attacked.
Darius was unwilling to own that his expedition had been useless. Yet his men were sick from cold, and their provisions were nearly at an end, so he had almost made up his mind to order the retreat. But while he still hesitated, the story tells that the Scythians sent one of their number to the great king, carrying with him as gifts a bird, a mouse, a frog, and five arrows.
The Persians demanded the meaning of these strange gifts, but the messenger had no answer to give. He had been but bidden to give them to the great king and return to his people.
Then Darius called together his council to consider what the offering might betoken.
The king himself thought that the presents were to show that the Scythians were ready to surrender their land, for on it the mouse found its home; their water, for in it dwelt the frog. The bird was a symbol of their war-steeds, and with the arrows showed that they were willing to lay down their arms. Darius was satisfied with his own explanation, but one of his councillors thought that the gifts had quite a different meaning.
"O Persians," he cried, "listen to my words and be wise. For unless ye become as birds and fly up into heaven, or go down like mice beneath the earth, or, becoming frogs, leap into the lake, ye will not escape being shot by these arrows."
As he listened to these alarming words, the king thought that after all perhaps this was the true meaning of the gifts, so he determined to return to the Danube. But the sick men and beasts of burden were left behind when the army set out, for they could not march as quickly as Darius wished. The groanings of these miserable men and the cries of the animals were heard by the Scythians, who soon discovered what had happened and set out in pursuit of Darius and his army.
Now the Ionians in charge of the bridge had long been tired of waiting for the return of the great king. He had perished, they said one to the other, and it would be well for them to break up the bridge and return to their homes.
Those who longed most to throw off their allegiance to the Persians muttered that even if the king had not already perished, he would soon do so, if he reached the Danube without provisions, to find the bridge was no longer there.
Miltiades, an Athenian, was strongly in favour of withdrawing, but Histiaeus, tyrant of Miletus, begged the Ionians to remain, for Darius would come back, of that he felt certain. Then turning to the other tyrants, he cried, "O ye tyrants, be sure of this, that if we leave the Persians to perish, the men of our cities will rise up against us, because it is the king who strengthens us in our power; and if he die, neither shall I be able to rule in Miletus, nor you in those cities of which ye are tyrants." Then the other tyrants agreed with Histiaeus that it would be for their own good to wait for the king.