Two works more than any others -- apart from the medieval poetry -- provided inspiration.
But not recently. I first read T. H .White's majestic The Once and Future King as a child, as you're supposed to read it, and it's never failed as a book to return to. Not least for its masterful narrative voice, suspended somewhere and nowhere in time between the then he's imagining and the time you're reading it. I know of no better lesson in how to tell an old tale with a modern voice.
The second inspiration is Mary Stewart's 'Merlin' trilogy: The Crystal Cave, The Hollow Hills and The Last Enchantment. The people in Stewart's books live in a plausible historical period, and she pulls off the remarkable feat of making everything credible, and giving you a reason to care at the same time.
I remember when the film of the musical Camelot came out.. I went with my mother to see it at the cinema. In those days they still played the national anthem at the end of the evening, and then there was always a rush to get out. My mother had the annoying habit of sacrificing the final moments of any film for the sake of standing up and getting out ahead of the crowd. I remember vividly the final lines of dialogue in which Richard Harris asks the young boy the night before the last battle his name. The boy says it's Tom Malory, and Richard Harris tells him he mustn't take part in the battle, but must leave now, and take with him the stories of the round table, and Arthur. We were on the landing outside the projection room and already at the head of the stairs when Richard Harris's voice was booming out, 'Run boy, Run boy.'
That was also an inspiration. It ties in with T. H. White's instruction to his young readers to one day read the pages of Thomas Malory and find out the things for themselves, which I did, finding two massive volumes of The Morte d'Arthur on two bottom shelves in Wolverhampton Central Library . . . Oh, it must have been about 1971. And so it all began.
Of course there was Simon Armitage's modern verse translation of The Green Knight, which showed what modern English can do to recapture the feel and flavour of the original alliterative verse and stay accessible to a contemporary audience.
Kenneth Sisam's Fourteenth Century Verse & Prose, the scourge of a first year English undergraduate back at the end of the 'seventies. It was in this book that I first encountered Middle English in all its thorny difficulty, its lyrical intensity, its flood of phonemic alliteration. Nothing apart from the original language quite puts you in the world described, which is where I've been heading ever since.