History is silent as to the part taken by Aristides in the impeachment of Miltiades, but there is no reason to believe that he opposed the measure of the Alcmaeonid party with which he acted, and which seems to have obtained the ascendency after the death of Miltiades.

In the year following the battle of Marathon, we find Aristides in the eminent dignity of archon.

In this office he became generally known by the title of the Just.

His influence, his official rank, the power of the party that supported him, soon rendered him the principal authority of Athens.

The courts of the judges were deserted, every litigant repaired to his arbitration--his administration of power obtained him almost the monopoly of it.
Still, however, he was vigorously opposed by Themistocles and the popular faction led by that aspiring rival.
By degrees; various reasons, the chief of which was his own high position, concurred to diminish the authority of Aristides; even among his own partisans he lost ground, partly by the jealousy of the magistrates, whose authority he had superseded--and partly, doubtless, from a maxim more dangerous to a leader than any he can adopt, viz., impartiality between friends and foes in the appointment to offices.
Aristides regarded, not the political opinions, but the abstract character or talents, of the candidates.