As a last effort to cure Britomart of her lovesickness, Glauce the nurse brings her to Merlin, the maker of the magic mirror. They hope he can tell them the name of the man Britomart saw in the mirror. Merlin agrees to their request: Not only does he reveal the name of Britomart's love, but he shows her the future of her line. The man in the mirror was a knight named Arthegall, the wizard says, who is related to King Arthur. The sons of Britomart and Arthegall will rule the Britons, and fight against the Saxons. After a time, the "wicked" Saxons will be victorious and the noble race of Britons will go into hiding. For 800 years, that race will be ruled wickedly in their own land, by the Saxons, the Danes, and then the Normans. Finally, a king will rise from the Britons to reclaim the throne--but here Merlin ends his predictions. Britomart is greatly encouraged to know that fate will smile so kindly on her love; she now is eager to find Arthegall. She determines to take up arms and dress like a knight, to enable herself to search for her love, who was lately in Faerie Land fighting alongside Arthur, as Merlin told her. There, she meets Redcrosse and (as we have seen) presses him for news of Arthegall.
Britomart, in fact, is a talented fighter; she is greater than all the female warriors that have been praised in history. And yet she is weakened by the good report that Redcrosse gives her of Arthegall; hearing praise of her loved one only deepens love's wound in her heart. Leaving Redcrosse to his own journey, she goes to the seacoast and pines for the man she cannot find. Suddenly, she sees a knight galloping toward her with his spear advanced; she takes up her own sacred spear and, charging, pierces his side and throws him to the ground. Feeling no pity, she continues onward, but Marinell (the strange knight) is wounded almost to death. His mother, a sea-nymph, hears of his dire condition and comes out of the sea to tend to him. They fear that he is beyond help; but still, they bind up his wound and bear him to the sea god Tryphon, who is skilled in healing.
Ignorant of all this, Britomart continues her journey; and Guyon and Arthur continue theirs, looking for the fair damsel Florimell, whom they saw fleeing a lusty shepherd. They come to a crossways and split up; Arthur's squire Timias also goes off his own way. It happens that Arthur chose rightly, for soon he sees the damsel, but she rides too quickly for him, and by night he has lost sight of her. He is distraught because he suspects that the damsel may be the Faerie Queene for whom he has been searching. Continuing in the morning, he meets a dwarf, who is chasing after the same girl. They continue the hunt together. Meanwhile, the squire Timias' path takes him after the lusty man who had been chasing Florimell. The villain runs ahead and gathers two friends to help lay a trap for the squire near a river that the lad must cross. When Timias' horse is in the river, they jump out and throw their spears at him; he is wounded in the thigh but still manages to cross the river. Once out, Timias gets his revenge, killing all three of them, but his wound has left him weakened, and he collapses on the riverbank. Luckily, a "noble hunteress" named Belphoebe comes upon the unconscious Timias (III.v.27). Filled with pity, she binds his wound, thus, saving his life, and she takes him back to her dwelling. When he recovers, however, the squire has a new wound: He has been struck by love. Unfortunately for him, Belphoebe is the model of "stedfast chastity" and has no desire to love a man; thus, Timias is left to the pangs of his lovesick heart (III.v.35).
Merlin's discourse on the history of the Britons takes up nearly all of Canto iii, certainly more than was required to convince Britomart that she should go after Arthegall. This is because its larger purpose is not to contribute to the poem's plot, nor even to the allegory. Spenser includes the long history to establish a direct connection between characters in The Faerie Queen--especially Arthur--and his sovereign, Queen Elizabeth. As much as the poet praises the Queen on her own merits, he also seeks to increase her stature and her place in history, by connecting her, in an unbroken chain, to the legendary heroes of Britain. Not only is she related to the great Arthur, but to the legendary founder of the Britons, Brute, and through him to the Trojans (this link will be brought up in detail in a later canto). This device of establishing ancestry has its roots in the New Testament--the Gospel of Matthew begins by tracing the line of Abraham through David to Christ. More applicable for Spenser is Virgil's connection in the Aeneid between Aeneas and Caesar Augustus--it is a secondary purpose of the poem to make that link, just as the justification of Elizabeth's rule is for The Faerie Queene. Of course, not all of Spenser's history can be proven; the earlier dates (pre-800) and people involve much speculation. Spenser's most important source is Geoffrey of Monmouth's History of the Kings of Britain, from which the legend of King Arthur first arose. Monmouth invented much of this "history", and so Spenser's interpretation may at certain points be a few levels removed from the truth. However, the important thing is that no one could disprove most of his history, and so by incorporating it into The Faerie Queene, Spenser helped to make it a more authoritative version. It was simpler, anyway, to view the history of British rule by the Britons as a single chain.
With the plot of the poem, however, Spenser moves farther and farther away from an unbroken chain in these cantos. The story of Britomart is supposed to form the central plot of the Book, and yet we see the subplots--like the pursuit of Florimell--taking over the story, even if they have little to do with Britomart. Spenser picks up and drops different plot lines almost indiscriminately--for example, we hear an extensive background of Marinell, but after he is wounded, he disappears and does not reenter the poem until a different book. If there is a flaw in Spenser's ability to create a complex world that draws on many sources, it is the confusion that sometimes confronts the reader at keeping track of all the characters and plotlines. We note that the poet himself became a bit confused--when he had the dwarf claim that Florimell left home after Marinell's death, he forgets that she was already seen on the run two cantos ago.
What these numerous subplots do add to the poem is an extension of its allegory, an extension best achieved by adding new characters. In Florimell, we have a woman who desires chastity but not in the same way as Britomart. She is not so much active as she is acted upon, as the object of men's desire. She is Beauty, the kind of beauty that will always inflame lust in men; since this is not balanced with active, forceful chastity (Britomart), Florimell becomes a much-abused character. Belphoebe has a better lot, and yet she, too, is lacking something when compared to Britomart. Belphoebe is chaste, and actively so, but she is static in her chastity. She is the limit of what chastity can be without leading to Christian love, which is why she is out in nature, unadorned, like the satyrs. It is the transition toward love within chastity that Spenser admires in Britomart.