Gringolet

In Arthurian legend, Gringolet is Sir Gawain's horse. A sturdy charger, Gringolet was known far and wide for his ability in combat. He appears in very many romances in several different languages, and the prominent Arthurian scholar Roger Sherman Loomis has noted that the French name Gringolet derived from either the Welsh guin-calet ("white and hardy"), or keincaled ("handsome and hardy").^[1] His earliest appearance is in Chrétien de Troyes' Erec and Enide; in that poem he is borrowed by Sir Kay to joust against Erec. Even Gringolet cannot prevent Kay from losing to the protagonist. In the Lancelot-Grail Cycle, Gawain wins Gringolet from a Saxon warrior; a different story of the acquisition is given in Wolfram von Eschenbach's Parzival, where the horse bears the mark and comes from the stable of the Grail castle.

In the Middle English poem Sir Gawain and the Green Knight, Gawain sets out atop Gringolet in search of the Green Chapel. Lines 600-604 of the poem describe Gringolet's ornate appearance in being readied for the journey:

The bridle was embossed and bound with bright gold;

So were the furnishings of the fore-harness and the fine skirts.

The crupper and the caparison accorded with the saddle-bows,

And all was arrayed on red with nails of richest gold,

Which glittered and glanced like gleams of the sun.

References

1. Roger Sherman Loomis, Arthurian tradition & Chrétien de Troyes (1949), p.158, 159 (books.google). Loomis defers to the suggestion by Tolkien *Gwyngalet 'white-hard'", and cites Heinrich Zimmer for the other etymology.