History of the Peloponnesian War
Thucydides
Thucydides. History of the Peloponnesian War. Crawley, Richard, translator. London and Toronto: J. M. Dent and Sons Ltd.; New York: E. P. Dutton and Co., 1914.
When their arrival was known at Miletus, orders came to them to leave half their squadron to guard Cnidus, and with the rest to cruise round Triopium and seize all the merchantmen arriving from Egypt. Triopium is a promontory of Cnidus and sacred to Apollo.