Like sheepdogs keeping watch on flocks in folds,
a nervous, bristling watch when the dogs get wind
of a wild beast rampaging down through mountain timber,
crashing toward the pens, and the cries break as he charges,
a din of men and dogs, and their sleep is broken, gone –
and so the welcome sleep was routed from their eyes,
guardsmen keeping the long hard watch that night.
Always turning toward the plain, tense to catch
some sign of the Trojans launching an attack.
– Homer
The Iliad, Book 10, lines 215-223. A description of how the nervous and unsleeping Achaeans remain on watch all night, for fear of a Trojan attack. An extended Homeric simile compares them to nervous sheepdogs guarding flocks and getting wind that a wild beast is rampaging through the pens.