Of all the monsters put together by the Greek imagination
the Centaurs (Kentauroi) constituted a class in themselves.
Despite a strong streak of sensuality, in their make-up,
their normal behaviour was moral, and they took a kindly
thought of man's welfare. The attempted outrage of Nessos on
Deianeira, and that of the whole tribe of Centaurs on the
Lapith women, are more than offset by the hospitality of
Pholos and by the wisdom of Cheiron, physician, prophet,
lyrist, and the instructor of Achilles. Further, the
Centaurs were peculiar in that their nature, which united the
body of a horse with the trunk and head of a man, involved
an unthinkable duplication of vital organs and important
members. So grotesque a combination seems almost un-Greek.
These strange creatures were said to live in the caves and
clefts of the mountains, myths associating them especially
with the hills of Thessaly and the range of Erymanthos.
[ Mythology of all races, Vol. 1, pp. 270-271 ]