The Iliad by Homer Book 23 Page 22

and that, whereas a man who knows what he is doing may have worse horses, but he will keep them well in hand when he sees the doubling-post; he knows the precise moment at which to pull the rein, and keeps his eye well on the man in front of him. I will give you this certain token which cannot escape your notice. There is a stump of a dead tree — oak or pine as it may be — some six feet above the ground, and not yet rotted away by rain; it stands at the fork of the road; it has two white stones set one on each side, and there is a clear course all round it.

It may have been a monument to some one long since dead, or it may have been used as a doubling-post in days gone by; now, however, it has been fixed on by Achilles as the mark round which the chariots shall turn; hug it as close as you can, but as you stand