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.
When those at Miletus received intelligence of them, they gave orders for half of the vessels to keep guard at Cnidus, and the other half to cruise around Triopium, and seize the merchantmen that were approaching from Egypt. This Triopium is a promontory running out from the Cnidian territory, and is consecrated to Apollo.