AS THE ROW OVER PLAGIARISM and Dan Brown’s The Da Vinci Code hit the courts this week, readers might be forgiven for thinking that writers are interested only in money and in themselves.

Dan Brown is the world’s highest-paid author, and the row is about the copyright to the central storyline of The Da Vinci Code — namely that Jesus married Mary Magdalene and had a child, and that the lineage has continued through time.

Whatever you make of that story, it is certainly true that Dan Brown’s earlier books, with their outlandish plots and pulpish prose, did not make him a bestselling author. Now that he has hit the jackpot, he acknowledges that he was able to make use of the research in Richard Leigh and Michael Baigent’s book, The Holy Blood and the Holy Grail (the book’s third author, Henry Lincoln, has declined to take part in the suit against Brown), but denies copyright infringement. The lawyers have been called in to settle the matter, and while it won’t be one of literary merit, it will be one of authorship and ownership. Just whose book is it anyway? The question of originality is an interesting one. We all know that Shakespeare never invented a plot; he worked on pre-existing material that allowed him to expand into his own mind. Much of Western culture depends on those writers, painters, musicians and sculptors who took themes and stories from the Bible and expressed them. Originality belonged to God. Humankind reflected and copied. The Humanist revolution of the Renaissance repositioned Man as the measure of all things, but not the essence of all things. Not until the Enlightenment was there a philosophical move to allow humankind a share in true creativity, and not before the Romantic rebellion was there really as sense of the poet/artist as primogenitor. When Wordsworth wrote The Prelude in 1798, and claimed that this was an epic poem whose subject was not, say, Paradise Lost or some grand theme of history, but “the growth of a poet’s mind”, he was changing the rules for ever.

It is the Romantics who have taught us to value originality in the modern sense. It is the Romantics who moved the personal away from the small private lyric expression and on to the vast stage of creative possibility. The artist becomes an inventor and a creative source in his own right.

Of course, any important work is stuffed with echoes and reworking of what has gone before. Influence is a good thing. New work is directly made out of what exists already, but it must bear the unmistakable mark of its reincarnation. It cannot be a copy. It cannot be cheap borrowing. The retelling or the remaking has to carry the past into the future.

No one is going to sue Philip Pullman for retelling Milton’s Paradise Lost, because he has made that text utterly his own. The original source is brought forward to a new generation, but Northern Lights is absolutely Pullman’s and not Milton’s.

J. K. Rowling’s critics claim that she has borrowed from everywhere, but Harry Potter is her own creation absolutely, and the world she has made will now go on to influence other work and other worlds.

What did James Joyce do in Ulysses but revive The Odyssey? Margaret Atwood has just written The Penelopiad, which also revisits The Odyssey, for the Canongate Myths series — whose brief to writers is to take an existing myth or legend and tell it again.

The recent poetry blockbusters have all been retellings: Ted Hughes on Ovid, Chrisopher Logue on Homer. Is any of that plagiarism? Kathy Acker used to take chunks of Dickens, or any writer she fancied, including me, and riff on them in her own wild and unexpected way. Is Dan Brown is riffing and recreating, or is he potboiling with someone else’s onions? The lawyers can decide all that. Meanwhile, Adrienne Rich’s The School Among the Ruins is out in paperback. Rich has been writing real poetry for 40 years. It is imaginative — opening new pathways for the reader. It is voiced — all poets speak in their own voice, at once intimate and powerful. It is authentic — both dependent on other material, yet entirely its own creation.

This book will not be a bestseller, and poets will never be the highest-paid writers in the world. Instead, poetry will go on cutting a hand-made path through mass-market insanity. For me, anyway, that path is the one that leads to the Chapel of the Grail.

Explore Books

• Book Extracts

• Book Reviews

• Books Group

• Audio Books

Times Recommends

• The 100 Best Books of the Decade
• The Times picks the 50 best paperbacks of 2009
• The conversation: James Ellroy