History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
But to some this was a sudden call, and it was not easy for them, except in a body and after waiting for one another, to go through the enemy's country; for that closed the way, lying just between. Nevertheless they hurried on.
But the Lacedaemonians, taking up the allies of the Arcadians that were present, invaded Mantinea, and encamping at the sanctuary of Heracles proceeded to ravage the country.