The dwarf, Una, and Prince Arthur ride until they reach Orgoglio the giant’s castle. They blow a horn at the gate, and Orgoglio leaves Duessa to see what the noise is. Orgoglio is ready to fight, and he lifts up his big club, but Arthur dodges it.
The blowing of a horn at the gate recalls the Biblical story of Jericho, where a seemingly impenetrable city wall fell to the simple blowing of a horn by one of the Israelites.
Orgoglio is struck down so hard that his club gets stuck in the ground. While he is trying to bring it up, Prince Arthur smites off his left arm, causing streams of blood to flow out. The giant lets out a fearsome bellow. Duessa hears it and rides out the gate on her seven-headed beast, but Arthur’s squire stops her. Duessa has a golden cup that she uses to perform magic, and she uses it to weaken Arthur’s squire’s courage.
Arthur is clearly stronger than the giant, as Redcross might have been if he’d had his shield with him. As was the case during Redcross’s earlier duel with one of the Saracens, Duessa intervenes in an attempt to give one of the competitors an unfair advantage.
Angered by the magic Duessa used on his squire, Prince Arthur smites off one of the heads of Duessa’s mount. A sea of blood comes out and stains Duessa’s clothes. Duessa’s beast can’t bear the pain of losing its head, so it throws her off.
Lots of heads get cut off over the course of the poem. The head can be seen as something’s root, and so beheading a creature is the fullest way to exterminate it (even if, in this case, Duessa’s many-headed creature lives on).
Meanwhile, Orgoglio the giant has recovered and comes charging at Prince Arthur. He brings his club down hard on Arthur’s shield and believes it impossible that any mortal could withstand such a blow. But as Arthur falls, a veil comes off his shield, and it lets out a blazing light that stuns both Orgoglio and Duessa’s beast. Orgoglio realizes that the shield represents a power that he won’t be able to overcome.
This scene with Arthur’s shield illustrates why Redcross was at such a disadvantage earlier without the ability to use his own shield. Like many evil characters, Orgoglio makes the mistake of underestimating the power and endurance of a righteous character like Arthur.
Prince Arthur smites off Orgoglio’s right leg below the knee, and the giant falls down like a tree, making the earth quake. Arthur goes over to give a mortal blow by chopping off the giant’s head. When the giant runs out of breath, his great body disappears, and all that’s left is an empty bladder.
The empty bladder that remains after Orgoglio is dead symbolizes how empty his life was. Though Orgoglio was a strong giant who managed to subdue Redcross, his lack of faith made him vulnerable when he faced a holy man like Arthur.
Duessa grieves to see the fall of Orgoglio. The squire captures her and brings her to Prince Arthur. Una thanks them for all that they’ve done for her and asks that they keep searching for the dungeon that holds the Redcross Knight. They force their way into the castle and find that it’s seemingly deserted.
The emptiness inside Orgoglio’s castle complements the empty bladder he left behind when he died. Evil characters often seem impressive on the surface, only for their true weakness to be revealed in death.
After searching around the castle, Prince Arthur and Una at last find a slow-moving old man who has the keys to every door in the castle. The old man is Ignaro, and he acted as a kind of foster father to Orgoglio. Ignaro doesn’t answer Arthur’s questions about the keys, so at last, Arthur just takes them.
This section is a strange and perhaps comic interlude that builds anticipation for the moment when Una and Redcross are finally reunited.
Prince Arthur tries the keys on various doors in the castle and finds great quantities of gold, but the floors are dirty with the blood of innocents who have been slain. He finds an altar that depicts the martyrdom of Christians. After much searching, Arthur finally finds an iron door and calls through it. A weak voice responds to him.
The juxtaposition of gold with the blood of innocents shows how evil men like the giant Orgoglio may be able to amass wealth but at a huge moral cost.
Prince Arthur breaks down the iron door. He has to descend a long way in the dark cell, but finally, he finds the Redcross Knight, who has lost all his muscles and is now very weak. Una runs to see him and cries tears of joy. She curses Fortune for being so bad to her and the knight lately.
The Redcross Knight shows visible signs of being weakened by his imprisonment, which perhaps also reflect a weakened spiritual condition—that he has become more doubtful after his defeat.
Prince Arthur asks what they should do about Duessa, the source of all their recent misfortune. Una suggests that instead of killing her, they should steal her robes and leave her naked. They do so, exposing Duessa as a wrinkled old witch. They let her go, and she flees into the wilderness. Una, the Redcross Knight, and Arthur stay in the giant’s castle for a while to rest.
For Duessa, a master of deception, the most fitting punishment is to leave her naked where she’ll be incapable of hiding what she truly is. Her flight into the wilderness suggests that this might not be the last time she appears in the poem, however.