Redcrosse, a.k.a. The Red Cross Knight, a.k.a. St. George, a.k.a. "That knight in Book 1," is a mighty mysterious fellow. While he's good with a sword, gallant to the ladies (well, sometimes), and always down for adventure, he's no Lancelot (or Prince Charming—take your pick).
In fact, it's no coincidence that we don't learn either of this character's names until well into Book 1: this dude's identity is not meant to be one-dimensional. In fact, we're given a clue right off the bat that this knight might be a bit identity-challenged when our narrator says he "seemed" to be a "full jolly knight," (I.i.1) instead of saying he just actually is one. This uncertainty is actually a bit unusual for Spenser's The Faerie Queene, a book jam-packed with not-so-mysteriously named things like "Patience" or "Repentance" (Sound weird? It is! But don't despair, just check out the Characterization section for the low-down on this technique called "Allegory.")
So, Redcrosse is a bit of an anomaly in a world where identity is sometimes painfully obvious.
But don't give up on him yet! While Redcrosse, man of mystery, might seem to be completely inaccessible, he's actually meant to be incredibly accessible; he's meant, in fact, to be kind of like you. Now, we know that you aren't in the habit of dueling wizards and killing dragons (right?), but we suspect that once in a while you probably make a mistake, take on way too much, go somewhere you shouldn't, or judge a friend way harshly.
Well, that's where you and Redcrosse have a lot in common, because Redcrosse isn't just some perfect, pre-packaged ready-to-go hero. He's trying to be a hero, and making a lot of errors on the way (including, literally, Error, who you can learn more about below)—sounds a lot more like you than, oh, a character named Contemplation, right?
The truth is that we don't know a whole lot about Redcrosse's identity because Redcrosse doesn't know a lot about Redcrosse's identity. In a lot of ways, we can read Book 1 of The Faerie Queene as a story less about heroism than about learning who we are and who we can be.
The fact that the guy who spend months stuck in the dungeon of a giant without even putting up a real fight ends up becoming the patron saint and hero of all of Britain—St. George—shows that what matters isn't never making mistakes, but always learning from them. Right on.
Of course, Redcrosse does get his act together. The man does slay a pretty serious dragon. So even though he's not perfect, Redcrosse does eventually fit his role as a savior to Una and her family. But Redcrosse's savior-cred doesn't just end there. As his name suggests (okay, yes, his name does suggest something), Redcrosse is symbolically associated with Jesus Christ in Christianity (which would have been the dominant religion when—and where—Spenser was writing).
As you probably know, Jesus performed his main work of salvation by sacrificing himself to be crucified, only to rise from the dead three days later in what's called the Resurrection. Crucifixion is not a pretty way to die, and because of his sacrifice and resurrection, a cross (and in Redcrosse's case, a cross still marked with blood) has come to symbolize Christian belief.
But Redcrosse's connection to Jesus goes beyond just his name. Even though he never literally dies, you might remember that twice during his final, epic battle with the dragon he almost dies. Both times, after being magically healed by a couple of very convenient fountains, he has a kind of resurrection, waking up the next day as if he had never been wounded or injured before: "So new this new-borne knight to batell new did rise" (I.xi.34).
Keyword there: new. Redcrosse, we might then say, embodies both moral and physical resurrection because he's always given a second chance, even when he doesn't deserve it and even when he doesn't expect it. What's nifty about Redcrosse is that he shows that an awesome savior and a regular-old-making-mistakes kind of guy can be found in a single person. Not bad, huh?