Hints of the Uffington Horse’s influence on Tolkien’s work that lean more toward the Horse’s Celtic origins are found in the Mearas, a myth-like race of horses in Middle-earth that are “as long-lived as Men”Tolkien, Return p. 1397.. Shadowfax, one of these horses, understands human speech and has “a lineage beyond time itself,” which adds to his mythic imageLeslie A. Donovan. “Middle-Earth Mythology: An Overview.” A Companion to J.R.R. Tolkien, edited by Stuart D. Lee. John Wiley & Sons, 2014, p. 104.. Being long-lived and able to understand the language of the Rohirrim—the latter of which hints at a close connection to humans—strongly recalls the Uffington Horse. This Horse is certainly long-lived as well and is reliant on interaction with the humans surrounding its hill to remain visible. Moreover, by matching the Uffington Horse’s myth-like status, the Mearas have a magical side to them. It is no surprise then that Felaróf, who was the first of the Mearas, had a white coat.
Shadowfax’s magical attributes are enhanced by the fact that he is the first of the Mearas to bear someone other than the King of RohanTolkien, Return p. 1397.. Gandalf the White, one of the five Istari, or Wizards, that were sent to Middle-earth, claims Shadowfax as his own: “He has come for me: the horse of the White Rider”Tolkien, Towers p. 658.. What we then see is that the colour white and the touch of magic, as both found in Rhiannon’s horse, are closely associated to Shadowfax: he has no white coat, but he is a descendant of a mythical white horse and his rider is a wizard with a strong connection to the colour white. What is also of note is that Rhiannon’s horse, by moving at a slow pace but being impossible to overtake, does not seem to adhere to what is deemed “normal” horse behaviour. Shadowfax has a similar tendency: when Grond is about to breach the gate of Minas Tirith during the siege of Gondor, Shadowfax is the only horse “among the free horses of the earth [to endure] the terror, unmoving”Tolkien, Return p. 1085.. It is obvious, then, that Shadowfax equals Rhiannon’s horse in multiple ways. Yet the Mearas can be linked to Beowulf’s treatment of the white horse as well: since the word “blanca” as explained in the notes to Slade’s translation of Beowulf hints at the white horse being the ancestor of all horses that come after it, the white horse Felaróf being the first of the Mearas is a familiar idea.