History of the Peloponnesian War

And what contributed to their getting the army out of the Peloponnese the more easily, was the misfortune of the Lacedaemonians at that time. For as the Athenians were pressing hard upon the Peloponnese, and especially upon their territory, they hoped to divert them from it most effectually, if they annoyed them in return by sending an army to their allies; especially as they were ready to maintain it, and were calling them to their aid, with a view to revolting.

Besides, they were glad to have a pretext for sending away some of the Helots; lest in the present state of affairs, when Pylus was occupied by an enemy, they might attempt some revolution.

Indeed through fear of their youth and great numbers, they even perpetrated the following deed: (for at all times most of the Lacedaemonian institutions were framed particularly with a view to the Helots, to guard against them.) They made proclamation, that as many of them as claimed to have done the state most service against the enemy should be picked out, professing that they would give them their liberty; thus applying a test to them, and thinking that those who severally claimed to be first made free, would also, through their high spirit, be most ready to attack them.