Henry Treece
Men of the Hills
1957
from the dustjacket of the 1958 Criterion edition:

About four thousand years ago, a horde of fair-haired, sun-worshiping warriors crossed over the sea to conquer and enslave the small, dark-skinned "Men of the Hills" who lived by planting barley and hunting with crude flint weapons.

Lalo the Otter was the son of the chief of the Men of the Hills. His was a rugged existence — hunting, learning the skills of battle, and growing into leadership. And what a savage introduction he had to manhood: on the same day he killed his first wolf he was forced to kill his first man!

Then the nomadic conquerors came, driving their cattle before them. They were everywhere, riding their strong horses, flinging their copper spears. The Men of the Hills gave way before the invaders. Before the day was out, Lalo saw his father slain and his kingdom destroyed by the Sun King's men.

How Lalo escaped and lived by his own strength and skill; how, helped by his guardian Kaa and accompanied by his dog Yan, he did his best to aid his beleaguered people; how he befriended Cradoc, the boy who would one day rule the wild nomads; and how the boys formed an allegiance that would bring a chance of survival to both — all these adventures are beautifully told in this dramatic novel.

As a saga of prehistoric England — a time so ancient that cave drawings were a novelty — this book paints a superb and thrilling picture of an exciting age. As a story of a lusty people, engaged in saving themselves from destruction, Men of the Hills is completely credible and sympathetic.