Andre Norton 
Horn Crown 

The story of how humanity first came to the Witch World—and almost doomed themselves as they discovered the dangers of their new home.   Long ago, after the Elder People deserted the place known as Witch World, a portal opened from another realm, bringing the people of Hallack to colonize the abandoned lands. But although the old inhabitants had gone, the Old Gods still existed to confound the new mortals beneath them.   This is the story of the first ones: Elron the Clanless and Gathea the Wise Woman, who sought their own separate fates in this new mountainous country; Iynne of Garn whose clan ventured into an unknown land of power and was seduced by sinister magic; and Gunnora, the Amber Lady, and her fight against Raidhan, Lady of the Dark Moon.   For any fan of the Witch World novels by Science Fiction Writers of America Grand Master Andre Norton, this is the must-have origin story for the adventures that have gripped lovers of sword and sorcery for generations. Horn Crown is the 5th book in the Witch World: High Hallack Cycle, but you may enjoy reading the series in any order.