AT THE BEGINNING of Sir Gawain and the Green Knight (c. 1375–1400) a mysterious figure, an aghlich mayster ‘awesome figure’ (136) bursts into the hall, marked as monstrous not only by his immense size, ‘On þe most on þe molde on mesure hyghe’ [One of the greatest on ground in growth of his frame] (137), but by his hue, oueral enker-grene ‘green as green could be’ (150). This marvel of a man carries an ax and a holly bough and issues a challenge to the awe-struck members of King Arthur's youthful yuletide court: an exchange of blows to test the pride and reputation of these knights, puzzle their wits, and, perhaps, frighten Guinevere to death (2456–60). Traditionally the Green Knight has been read as a manifestation of ‘evil’ come to threaten, test, and tempt the Round Table. The poem engages directly with the question of his Otherness, and critics have devised ‘Other’ ways of interpreting him – devil, Green Man, nature God, even Saracen – and the woman he serves, Morgan le Fay. Less attention has been given to his human alter ego, Lord Bertilak, magically transformed by Morgan. While critics often fixate on the secondary aim of Morgan's plan – traumatizing Guinevere – as the Green Knight, Lord Bertilak instructs Arthur's court in humility, constancy, and mercy, appearing at first as a terrifying (but beautiful) entity; the tallest of men (only half a giant), whose challenge is to the very essence of Arthurian knighthood and chivalry. Rather than an Otherworldly specter sent by a supernatural enchantress to haunt Arthur's court and his wife, however, the Green Knight only passes as Other. He is an elaborate illusion woven by the very-mortal Morgan to test the renown of the Round Table, and without her magical intervention he is as human as Gawain himself. Bertilak embodies ideal courtesy and chivalry, tempered by humanity and the symbiotic relationship between the realms of fantasy and reality necessary for instructing the human world, specifically Gawain, in its failures in an attempt to save it.