A wallowing Boar still enter'd first,
Muddying the stream. The Horse, enrag'd,
To take his part a man engag'd,
Who mounts his back, and shoots a dart,
Right aim'd, that pierc'd the offender's heart.
"'Tis well you call'd on me for aid,"
The horseman said, "I'm well repaid,
On such a useful beast to sit:"
Then forc'd into his mouth a bit.
When thus the sorrowing Horse, "I sought
For vengeance on a venial fault,
And madly servitude have caught."
Ye choleric learn a lesson here,
That vengeance may be paid too dear.
Source: Boothby - Phaedrus 4.4.
Click here for a SLIDESHOW of all the Harrison Weir images. As you can see, the horse's opponent in this illustration is a stag, not a boar - you can find the fable told both ways.