History of the Peloponnesian War
Thucydides
Thucydides. The history of the Peloponnesian War, Volume 1-2. Dale, Henry, translator. London: Heinemann and Henry G. Bohn, 1851-1852.
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.