In Stewart's obituary, The New York Times described her as an "author of romantic thrillers who jumped genres in her 50s to create an internationally best-selling trilogy of Merlin books, reimagining the Arthurian legend from a sorcerer's point of view," and said, "Reading Geoffrey of Monmouth's History of the Kings of Britain, she was inspired to retell the story of King Arthur as seen by Merlin, the king's adviser and house magician. The trilogy introduced her work to a new generation and, in many cases, to male readers for the first time. ... The books, set in the fifth century, were praised for their unusual blend of fantasy and historical detail."[4]
The Guardian spoke of Stewart's own considerations as well as that of her publishers: "The Crystal Cave (1970), the first of a fictional trilogy about Merlin, arose from her fascination with Roman-British history. The unexpected switch at first alarmed her publishers – she was, unusually, published by the same firm, Hodder & Stoughton, for her entire career, never using an agent – but the book was a No 1 bestseller for weeks. Of all her books, The Crystal Cave is the most enduring, and has lost none of its freshness. It is a masterful imagining of Merlin's upbringing that vividly evokes fifth-century Britain. The Hollow Hills (1973) and The Last Enchantment (1979) completed the trilogy, earning Stewart favourable comparisons with another leading Arthurian, TH White. They were the books of which she was most proud."[5]
Kirkus Reviews said with a touch of disdain, "With its mythic mists and galloping legends, fifth century Britain is fair game and Miss Stewart takes to whole cloth with a couturier's skill. ... Period play, ripe and windy, for ladies easily lulled--and there are many of them."[6]
