There is a prequel called Horn Crown, http://www.goodreads.com/book/show/11...

Andre Norton enthralled readers for decades with thrilling tales of people challenged to the limits of their endurance in epic battles of good against evil. None are more memorable than her Witch World novels.

Far from the besieged home of Simon and Jaelithe, in peaceful Norsdale, we meet Gillan, who longs to leave her dull life in a secluded country abbey. But when her wish comes true, she finds more than a little adventure. As she ventures out, not only is her life in danger, but also the power that lies within her, waiting to be discovered.