The device of a pair of characters, a brother and a sister named Edred and Elfrida, who travel back in time from
Edwardian England, guided by a magical character,
Mouldiwarp, always meeting a similar pair of characters in each of the earlier centuries that they visit, is the central plot device in the book.
J. R. R. Tolkien's unpublished attempt at a time travel novel,
The Lost Road functions in the same way.
The Lost Road has father/son pairs named Edwin/Elwin, Eadwine/
Aelfwine, Audoin/Alboin, Amandil/
Elendil (all meaning "Bliss-friend/Elf-friend" in Old English, Old High German, and Lombardic). Nesbit's Edred and Elfrida, too, have according to the Tolkien scholar Virginia Luling "intriguing[ly]" similar
Old English names to Tolkien's paired characters; Edred is "Bliss-counsel", while Elfrida is "Elf-strength". ==References==