History of the Peloponnesian War

Meanwhile intelligence reached them from their friends in Tegea, that unless they came there quickly, Tegea would go over from them to the Argives and their allies, and that it had all but done so.

Upon this then succour was given them by the Lacedaemonians and their helots in full force, with vigour, and in such a way as had never been done before.

They advanced to Orestheum, in the Maenalian territory; and commanded those of the Arcadians who were their allies to muster and march close after them to Tegea; while they themselves, after coming all of them as far as Orestheum, from that place sent back home the sixth part of their force, in which were included those who were too old or too young for foreign service, to protect their property at home, and with the remainder of their army arrived at Tegea, where their allies from Arcadia joined them not long after. They also sent to the Corinthians.

Boeotians, Phocians, and Locrians, with orders to reinforce them as quickly as possible at Mantinea. But to these the notice was short, and it was not easy, except in a body, and after waiting for each other, to cross the enemy's territory; for it closed up the communication, lying just in the way of it: however, they made all haste notwithstanding.

The Lacedaemonians, meanwhile, taking with them their Arcadian allies who had joined them, invaded the territory of Mantinea, and having encamped near the temple of Hercules, laid waste the land.