Vaulting on his war-steed, Georgos now rides off with Una and the dwarf, and after crossing a wilderness enters a forest, where before long he descries the mouth of a cave, into which he feels impelled to enter.  No sooner has he done so than he encounters a dragon,—­the personification of Heresy and Error,—­which attacks him with fury.  A frightful battle ensues, in the course of which the Red Cross Knight is about to be worsted, when Una’s encouragements so stimulate him that he slays the monster.

On seeing the exhaustion of her companion, Una realizes he will require rest before undertaking further adventures, and therefore eagerly accepts an invitation tendered by a venerable old hermit who meets them.  He leads them to his cell, where, after entertaining them all evening by pious conversation, he dismisses them to seek rest.  His guests have no sooner vanished than the hermit, Archimago,—­a personification of Hypocrisy,—­casts aside his disguise, and summons two demons, one of whom he despatches to Hades to fetch a dream from the cave of Morpheus.  This dream is to whisper to the sleeping Red Cross Knight that Una is not as innocent as she seems, while the other demon, transformed into her very semblance, is to delude the knight on awakening into believing his companion beneath contempt.  This plot is duly carried out, and the Red Cross Knight shocked by the behavior of the sham Una departs immediately, bidding the dwarf follow him.  Riding along in a state of extreme disgust and irritation, the Red Gross Knight soon encounters Sansfoi,—­Faithlessness,—­accompanied by a lady clad in red, who is Duessa,—­a personification of Mary Queen of Scots, and also of falsehood and popery.  The two knights immediately run against each other, and, when Georgos has slain his opponent, the lady beseeches him to spare her life, exclaiming her name is Fidessa and that she is only too glad to be saved from the cruel Sansfoi.  Deluded by her words and looks, the Red Cross Knight invites her to accompany him, promising to defend her from her foes.

They are riding along together amicably, when the knight plucks a blossoming twig to weave a garland for his companion, and is dismayed to see blood trickle from the broken stem.  Questioning the tree from whence the branch was taken, Georgos learns that a knight and his wife have been transformed into plants by Duessa, who does not wish them to escape from her thraldom.  During this explanation, Georgos fails to notice that the lady in red trembles for fear her victims may recognize her, nor does he mark her relief when she perceives her present disguise is so effective that no one suspects she worked this baleful transformation.