This one is probably not so well known, and certainly not as much as it should be. That's probably because it's by this Christian author - Stephen Lawhead, who's also written a few others, mostly located somewhere on the British Isles and somewhere in the more medieval period.
In this one, though, he's undertaken the task of one of the more well-known folk stories of all time - Robin Hood. And he's put a bit of an interesting twist on it. Well, a few, actually, but this is the main one; he's in Wales. He's pushed it back into the time of King William II of England, when the Normans were in power, and they were attempting (unsuccessfully) to expand over into Wales.
And this is where he's rebirthed Robin Hood; rebirthed as the young prince Bran ap Brychan, heir to the throne of Elfael, a fairly rebellious, stubborn and charming sort of guy, who liked the ladies. It seems quite removed from the Robin Hood we know. And, indeed, the name Hood only crops up once (probably a throwaway), as a misheard word.
Bran's father goes to Lundein (London) to swear allegiance to William (he's delayed for so long because he's proud and stubborn). But he's delayed for too long and gets met on the way by a Norman force, who have been "given" his land because he took too long. As such, he and almost the entire warband are killed. Bran, with the one remaining member of the warband, attempts to reclaim Elfael from the Normans, but is captured, outlawed and nearly killed. A healer/bard/wise woman finds Bran and nurses him back to health, and in the process teaches him what he needs to know to become a good leader.
And so Bran, with what is left of Elfael, launches what can only be described as a guerilla war against the Normans; using a combination of stealth and superstition, they fight back as best they can.
It's a great read, combining historical fiction with adventure. And this guy really knows his history; he's researched all the facts about the different eras and such. And he actually has a sound historical basis for why he put Robin Hood in Wales, which I think might be an Afterword in this book; though it may be in Scarlet or Tuck, the second and third in the trilogy.
If you're thinking, but ohhh, it'll be so different without all the things I loved in Robin Hood - it's got Little John, it's got Friar Tuck, Marian (though she's called Merian), and in the latter books there's Will Scarlet as well. Bran's an unrivalled shot with the bow (a crucial point to the series, as a matter of fact), and he's still taking from the rich and giving to the poor. But it's all a bit different, and it's a really refreshing and interesting new way of looking at it.
I'd highly recommend to anyone having a look at this one, and indeed the whole trilogy; guys at uni, if you're interested, I can lend you my copies.