The poem then breaks into a first-person account of the birth of the flower-maiden Blodeuwedd, and then the history of another one, a great warrior, once a herdsman, now a learned traveller, perhaps Arthur or Taliesin himself. After repeating an earlier reference to the Flood, the Crucifixion and the day of judgment, the poem closes with an obscure reference to metalwork.
There are contemporary passing allusions to the Battle of Trees elsewhere in the mediaeval Welsh collections: The Welsh Triads record it as a "frivolous" battle, while in another poem of the Book of Taliesin the poet claims to have been present at the battle.
According to a summary of a similar story preserved in Peniarth MS 98B (which dates from the late sixteenth century) the poem describes a battle between Gwydion and Arawn, the Lord of Annwn. The fight broke out after the divine plowman Amaethon stole a dog, a lapwing, and a roebuck from Arawn. Gwydion ultimately triumphed by guessing the name of one of Arawn's men, Bran (possibly Bran the Blessed).
In the Mabinogi story of the childhood of Lleu Llaw Gyffes, Gwydion makes a forest appear to be an invading force.
The Cad Goddeu, which is difficult to translate because of its laconic allusiveness and grammatical ambiguity, was the subject of several nineteenth-century speculative commentaries and English renderings. Thomas Stephens held the poem to concern "a Helio-Arkite superstition, the metempsychosis of a Chief Druid, and a symbolical account of the Deluge". Gerald Massey's monumental work on African origins suggested that the poem reflected Egyptian religion.
David William Nash believed it was a poor-quality twelfth-century romance overlaying a romance or story of the Arthurian era and put together with other poetic fragments. W. F. Skene rejected the antiquity of the prose account and thought the poem reflected the history of the north country during the Irish incursions. Watson followed Skene and Ifor Williams posed the question 'What about the Battle of Celyddon Wood?'
Robert Graves took up a speculation that had been considered and rejected by Nash; that the trees that fought in the battle correspond to the Ogham alphabet, in which each character is associated with a particular tree. Each tree had a meaning and significance of its own, and Gwydion guessed Bran's name by the alder branch Bran carried, the alder being one of Bran's prime symbols. Graves argued that the original poet had concealed druidic secrets about an older matriarchal Celtic religion for fear of censure from Christian authorities. He suggested that Arawn and Bran were names for the same underworld god and that the battle was probably not physical but rather a struggle of wits and scholarship: Gwydion's forces could only be defeated if the name of his companion, Lady Achren ("Trees"), was guessed and Arawn's host only if Bran's name was guessed.
Graves, following Nash, accepted that the poem is a composite of several different sections, among which he named a Hanes Taliesin (History of Taliesin) and a Hanes Blodeuwedd (History of Blodeuwedd).
Marged Haycock and Mary Ann Constantine reject the idea that Cad Goddeu encodes ancient pagan religions as Graves believed but rather see it as a burlesque, a grand parody of bardic language. Francesco Bennozo argues that the poem represents ancient fears of the forest and its magical powers.
John Williams used a version of Cad Goddeu (loosely) translated into Sanskrit for his piece "Duel of the Fates" in his score for the film Star Wars Episode I: The Phantom Menace. He also directly based the second movement of his 2004 Horn Concerto on the "Battle of the Trees."
Singer-songwriter Tori Amos was inspired by the story of Cad Goddeu for her song Battle of Trees, which appears on Night of Hunters, a narrative concept album, presented as a 21st-century song cycle. This song, a variation on Erik Satie's Gnossienne No 1 , uses references to Cad Goddeu to reflect on the power of language as a battle-ready weapon.
- ^ Thomas Stephens, Literature of the Cymry, 1848, quoted in Nash, op cit.
- ^ Gerald Massey, Book of the Beginnings vol 1, reprinted 2002, Kessinger Publishing, ISBN 0-7661-2652-8, page 361.
- ^ David William Nash, Taliesin, Or, The Bards and Druids of Britain: A Translation of the Remains, J. R. Smith, 1848.
- ^ W. F. Skene, The Four Ancient Books of Wales, 1868, republished 2004 Kessinger Publishing, ISBN 0-7661-8610-5, page 206
- ^ Lesnie, Melissa. "Tori Amos: Classical Music Huntress". Limelight Magazine. Retrieved 3 August 2011.
- ^ Keefe, Jonathan. "Album Review: Tori Amos, Night of Hunters". Slant Magazine. Retrieved 3 August 2012.