There is an inscription in the Fëanorian characters (Tengwar, an alphabet Tolkien has devised for High-Elves) in the first pages of every History of Middle-earth volume, written by Christopher Tolkien and describing the contents of the book.
In the fiction of J. R. R. Tolkien, Beleg is a major character who appears in numerous books, tales and poems about the First Age of Middle-earth such as The Silmarillion, The Lays of Beleriand and the Children of Húrin.
The poem was published after the author's death by his son Christopher in The Lays of Beleriand, the third volume of The History of Middle-earth.