Raymond H. Thompson (Author)  interviewed Rosemary Sutcliff for the periodical Avalon to Camelot in 1986. In the introduction he wrote:

Though perhaps best known for historical novels set in Roman Britain, such as The Eagle of the Ninth (1954), Rosemary Sutcliff has written some of the finest contemporary recreations of the Arthurian story. She introduces us to Arthur in The Lantern Bearers (1959), a book for younger readers that won the Carnegie Medal, and in Sword at Sunset (1963) she continues his tale in his own words. She has also retold the Arthurian legend with clarity and elegance in Tristan and Iseult (1971), The Light Beyond the Forest (1979), The Sword and the Circle (1981), and The Road to Camlann (1981). Her later novels were set in the more recent past, but she returned to Dark Age Britain for her … novel The Shining Company (London: Bodley Head), which is based upon the Gododdin. This poem, composed about 600 A.D. in North Britain by the bard Aneirin to commemorate a band of British warriors who fell in battle against the Angles, is of special interest in that it provides us with the earliest mention of Arthur’s name and Sutcliff’s novel preserves the Arthurian echoes.

Source:  Interview with Rosemary Sutcliff | Robbins Library Digital Projects.