White places his King Arthur in England, which Arthur calls Gramarye, during the Dark Ages, about the year 1200. Most historians think the actual King Arthur—if there was one—lived much earlier, probably around A.D. 460.

Malory, White's model, also portrayed Arthur as a medieval king. Even though White knew much about the medieval period, he intentionally employs anachronisms—things or characters that people at the time of the story could not have known—such as Merlyn's discussions of communism, Darwin, and other modern topics. White does this partially for humor but also to demonstrate that the problems people confronted in the Dark Ages were much like those of the twentieth century.