The Crystal Cave

The Crystal Cave came out in 1970, and it was the first of a quintet of novels in which Mary Stewart retold the Arthurian legend; the next of them was The Hollow Hills.

Its narrator is Myrddin Emrys, known in the English tradition as Merlin. The Romans have recently withdrawn from Britain, which is now split between a number of kingdoms loosely joined under a High King, and Merlin's mother is a Welsh princess who has never named his father. The story runs from his sixth birthday to his early manhood.

He is small for his age and often ill-treated, and every so often he has visions of things he could not know by ordinary means; it is this, along with his unknown parentage, that leads people to call him a devil's son. A hermit called Galapas teaches him how to work with his gifts, and in time he reaches the court of Ambrosius Aurelianus in Brittany, where the career that the rest of the series depends on begins, and where he first becomes useful to men with power.