Book I is centered on the virtue of Holiness as embodied in the Redcross Knight. He and his lady Una travel together as he fights the dragon Errour, then separate as the wizard Archimago tricks the Redcross Knight in a dream to think that Una is unchaste. After he leaves, the Redcross Knight meets Duessa, who feigns distress in order to entrap him. Duessa leads the Redcross Knight to captivity by the giant Orgoglio. Meanwhile, Una overcomes peril, meets Arthur, and finally finds the Redcross Knight and rescues him from his capture, from Duessa, and from Despair. Una and Arthur help the Redcross Knight recover in the House of Holiness, with the House's ruler Caelia and her three daughters joining them; there the Redcross Knight sees a vision of his future. He then returns Una to her parents' castle and rescues them from a dragon, and the two are betrothed after resisting Archimago one last time.

What does the redcrosse knight represent in the faerie queene? Okie... think carefully first, then make a decision:
The relevant information to answer the above question is: Book I is centered on the virtue of Holiness as embodied in the Redcross Knight. So, the answer is the virtue of Holiness.