History of the Peloponnesian War

Accordingly these cursed ones were driven out by the Athenians, driven out again by Cleomenes of Lacedaemon and an Athenian faction; the living were driven out, and the bones of the dead were taken up; thus they were cast out. For all that, they came back afterwards, and their descendants are still in the city.

This, then, was the curse that the Lacedaemonians ordered them to drive out. They were actuated primarily, as they pretended, by a care for the honor of the gods; but they also knew that Pericles, son of Xanthippus, was connected with the curse on his mother's side, and they thought that his banishment would materially advance their designs on Athens

Not that they really hoped to succeed in procuring this; they rather thought to create a prejudice against him in the eyes of his countrymen from the feeling that the war would be partly caused by his misfortune.

For being the most powerful man of his time, and the leading Athenian statesman, he opposed the Lacedaemonians in everything, and would have no concessions, but ever urged the Athenians on to war.