V. When Datis was sent by Darius, nominally to punish the Athenians for the burning of Sardis, but really to enslave the whole of Greece, he landed at Marathon, and commenced laying waste the country.  Of the ten generals appointed by the Athenians for the conduct of the war, Miltiades had the highest reputation, while Aristeides held the second place.  He used his influence in the council of war to support the proposition of Miltiades to fight the enemy at once, and also, as each general had sole command for one day, when his day came round, he gave it to Miltiades, thus teaching his colleagues that obedience to those who know how to command is not any disgrace, but a noble and useful act.  By this means he was enabled to put an end to the rivalries between the generals, and to strengthen Miltiades by concentrating in him the power which had before been passed from hand to hand.  In the battle the Athenian centre was hard pressed, as the Persians resisted longest in that part of their line which was opposed to the tribes Leontis and Antiochis.  Here Themistokles and Aristeides each showed conspicuous valour, fighting side by side, for the former was of the tribe Leontis, the latter of the tribe Antiochis.  After the victory was won, and the Persians forced into their ships, they were observed not to sail towards the Archipelago, but to be proceeding in the direction of Athens.  Fearing that they might catch the city defenceless, the Athenians determined to hurry back with nine tribes to protect it, and they accomplished their march in one day.  Aristeides, with his own tribe, was left to guard the prisoners and the plunder, and well maintained his reputation.  Although gold and silver was lying about in heaps, with all kinds of rich tapestry and other countless treasures, he would neither touch them himself nor allow the others to do so, though some helped themselves without his knowledge.  Among these was Kallias, the torch-bearer in the Eleusinian mysteries.  One of the prisoners, taking him for a king because of his long hair and fillet, fell on his knees before him, and having received his hand as a pledge for his safety pointed out to him a great store of gold concealed in a pit.  Kallias now acted most cruelly and wickedly.  He took the gold, and killed the poor man for fear that he should tell it to the others.  It is said that ever afterwards the descendants of Kallias were jeered at by the comic poets, as being of the family of the man who found the gold in the pit.

Immediately after those events, Aristeides was chosen as Archon Eponymus, that is, the archon who gives his name to the year.  Demetrius of Phalerum says that he filled this office shortly before his death, and after the battle of Plataea.  But in the public records of Athens one cannot find any archon of the name of Aristeides among the many who filled the office after Xanthippides, in whose archonship Mardonius was defeated at Plataea, whereas the name of Aristeides does occur next to that of Phanippus, in whose archonship the victory at Marathon was won.