In The Faerie Queene, Spenser creates an allegory: The characters of his far-off, fanciful "Faerie Land" are meant to have a symbolic meaning in the real world. In Books I and III, the poet follows the journeys of two knights, Redcrosse and Britomart, and in doing so he examines the two virtues he considers most important to Christian life--Holiness and Chastity. Redcrosse, the knight of Holiness, is much like the Apostle Peter: In his eagerness to serve his Lord, he gets himself into unforeseen trouble that he is not yet virtuous enough to handle. His quest is to be united with Una, who signifies Truth--Holiness cannot be attained without knowledge of Christian truth. In his immature state, he mistakes falsehood for truth by following the deceitful witch Duessa. He pays for this mistake with suffering, but in the end, this suffering makes way for his recovery in the House of Holiness, aided by Faith, Hope, and Charity. With newfound strength and the grace of God, he is able to conquer the dragon that represents all the evil in the world.
In a different manner, Britomart also progresses in her virtue of chastity. She already has the strength to resist lust, but she is not ready to accept love, the love she feels when she sees a vision of her future husband in a magic mirror. She learns to incorporate chaste resistance with active love, which is what Spenser sees as true Christian love: moderation. Whereas Redcrosse made his own mistakes (to show to us the consequences of an unholy life), it is not Britomart but the other characters in Book III who show the destructive power of an unchaste life. Spenser says in his Preface to the poem that his goal is to show how a virtuous man should live. The themes of Book I and Book III come together in the idea that our native virtue must be augmented or transformed if it is to become true Christian virtue. Spenser has a high regard for the natural qualities of creatures; he shows that the satyrs, the lion, and many human characters have an inborn inclination toward the good. And yet, he consistently shows their failure when faced with the worst evils. These evils can only be defeated by the Christian good.
High on Spenser's list of evils is the Catholic Church, and this enmity lends a political overtone to the poem, since the religious conflicts of the time were inextricably tied to politics. The poet is unashamed in his promotion of his beloved monarch, Queen Elizabeth; he takes considerable historical license in connecting her line with King Arthur. Spenser took a great pride in his country and in his Protestant faith. He took aim at very real corruption within the Catholic Church; such attacks were by no means unusual in his day, but his use of them in an epic poem raised his criticism above the level of the propagandists.
As a purely poetic work, The Faerie Queene was neither original nor always remarkable; Spenser depends heavily on his Italian romantic sources (Ariosto & Tasso), as well as medieval and classical works like The Romance of the Rose and The Aeneid . It is Spenser's blending of such diverse sources with a high-minded allegory that makes the poem unique and remarkable. He is able to take images from superficial romances, courtly love stories, and tragic epics alike, and give them real importance in the context of the poem. No image is let fall from Spenser's pen that does not have grave significance, and this gives The Faerie Queene the richness that has kept it high among the ranks of the greatest poetry in the English language.