King of the North — Harry Turtledove

Just when he thought he could settle down to enjoy peace in his time, Gerin the Fox is told by the god Biton's new Voice (rather to Biton's annoyance, Gerin had married and so disqualified Biton's previous Voice) that: "Danger overhangs the Northlands like bunches of ripe grapes hanging down from the vine." Any mention of grapes makes Gerin nervous, for it suggests that the Sithonian god Mavrix may be interested once more in affairs of the Northlands; whenever that playful, malevolent, highly civilized god notices him and his domain, dreadful things have a way of happening.

But times change, and Gerin's newest enemies, the Gradi, have gods of their own--cold, fierce gods, who, as soon as an area is conquered, destroy its ecology, making it uninhabitable to any who do not worship them.

To fight this menace, Gerin will have to invoke all the help he can get, from Mavrix to Baivers to the crude gods of those who live beneath the ground. And Gerin will have to survive this war of the gods before he can consolidate the Northlands, sow civilization along with wheat and barley, and truly call himself King of the North.