The sprites go back to their master, Archimago, and report their failure. Archimago transforms one of the sprites to look like a young squire, then puts the squire in bed next to the sprite that looks like Una. Archimago then wakes the Redcross Knight and tells him to go witness the shameful things that his supposedly chaste lady is doing.
Many of the villains in the poem have access to a sort of shapeshifting magic, able to disguise not only their own appearances but the appearances of others as well.
The Redcross Knight sees the two sprites disguised as Una and the squire, entwined together in bed, and he nearly slays them but is restrained by Archimago. He goes back to his own bed in torment, and at dawn, he and the dwarf speed away on their horses.
The illusion magic of Archimago is convincing and it leads Redcross to mistakenly believe that his lady Una has been unfaithful to him.
Una wakes up and weeps to see that the Redcross Knight and the dwarf are gone. She tries to catch up with them in vain. With Una alone in the woods, Archimago sees an opportunity. The crafty sorcerer decides to disguise himself as the Redcross Knight.
Without a knight like Redcross around to protect her, a lady like Una is vulnerable. With a couple of notable exceptions, most of the virtuous women in the poem are helpless, perhaps reflecting ideas about gender when the poem was written.
Meanwhile, the real Redcross Knight, who is in fact St. George (a famous British dragon-killing saint), happens to run into an armed Saracen (a Muslim) The Saracen’s shield contains the words Sans foy (“without faith”). Next to Sansfoy the Saracen is a lady (Duessa) in scarlet who wears a Persian-style crown. She is the Saracen’s lover, and she asks him to fight the Redcross Knight.
Although medieval Europe is most associated with Christianity, Spain was an Islamic country during much of the Middle Ages, and the Crusades brought many Christian European soldiers to the Middle East. Muslims had mostly been driven out of Spain by Spenser’s time, but they were stock villains in medieval romances that would have inspired The Faerie Queene.
The Redcross Knight and Sansfoy the Saracen battle each other with the ferocity of two rams. Sansfoy finds he’s unable to hurt the knight and curses the cross for protecting Redcross. At last, the Redcross Knight strikes the Saracen down, and he dies.
The fact that Sansfoy (whose name literally means “without faith”) is defeated by the holy Redcross knight suggests that, from Spenser’s perspective, Protestant Christianity is more powerful than rival religions.
After seeing her lover Sansfoy die, the scarlet lady (Duessa) pleads for mercy from the Redcross Knight. The knight is moved and asks who she is. In tears, the lady tells the story of how she was the daughter of an emperor. She was engaged to a fair prince, but the prince was suddenly slain. Soon after, the proud Saracen Sansfoy found her and took her with him. Sansfoy had two younger brothers: Sansjoy and Sansloy.
Duessa is one of the most important recurring characters in the story. While Una is associated with the color white, Duessa is associated with scarlet, which suggests from the very beginning that she might not be as innocent or as helpless as she appears (since the color red can be associated with blood, or perhaps fire).
The lady, whose gives her name as Fidessa, tells the Redcross Knight that she is now alone and asks him to show her pity. The knight pledges to protect her, and they begin to ride together.
Fidessa is a name that suggests faithfulness, and so it seems at first that Fidessa is a good match for the Redcross Knight.
The Redcross Knight and Fidessa reach two big trees, where they decide to take shelter from the heat in the shade. The knight gets the idea of making a garland for the lady, but as he breaks off a branch, blood trickles out of the hole.
The blood trickling out of the tree foreshadows that something about the current situation isn’t right and recalls the scarlet color associated with “Fidessa.”
A voice calls out, warning the Redcross Knight and Fidessa to run away. The voice is the tree—he reveals that he was once a man named Fradubio, but he was turned into a tree by a cruel witch. The knight asks who the witch was, and Fradubio says it was Duessa, a sorceress who has ensnared many knights with her tricks.
Being turned into a tree was a fairly common mythological punishment. The similarity between the names Fidessa and Duessa is a big clue for readers about Fidessa’s real identity, but the characters in the poem often realize things after the readers do.
Fradubio used to love a lady who also got turned into a tree, whose name was Fraelissa. He tells the story: Fraelissa and the disguised sorceress Duessa have a contest to see which of them Fradubio considers the fairest. Seeing that she can’t win, Duessa decides to use her magic and turns Fraelissa into a tree. Duessa then becomes Fradubio’s lady.
Like Archimago, Duessa is able to disguise her appearance. There are limits to her magic, however—even her illusions aren’t enough to compete with the real Fraelissa, which is why she turns her into a tree.
Fradubio continues his story: At first, he and Duessa are happy. Then one day, Fradubio sees Duessa bathing, which reveals her true form as an old woman. Fradubio makes a plan to run away, but Duessa senses the change in his manner. She also turns him into a tree, placing him right next to Fraelissa (who is also still a tree).
Another limit to magic like Duessa’s is that it isn’t permanent, and so false characters risk getting caught.
Fradubio tells the Redcross Knight that he will remain stuck in tree form until he comes in contact with the water of a living well. Fidessa overhears this—it turns out that Fidessa is in fact just a new disguise for Duessa. Duessa looks afraid and faints, but the Redcross Knight doesn’t realize the truth about her identity.
In real life, water is often a symbol of purity or of the act of purifying (such as in baptism), and it sometimes plays this role in the poem as well, as it does here where it is revealed to be the cure for Fradubio’s condition.