ONE of the many exhibits in the Salisbury Museum’s wonderful HisWorld exhibition (a remarkable 10,000 visitors and counting) is a letter that the young Terry Pratchett wrote to the writer, JRR Tolkien.

To Pratchett’s surprise, Tolkien wrote back. ‘He must have had a sackful of letters from every commune and university in the world,’ he recalled in A Slip of the Keyboard, ‘written by people whose children are now grown-up and trying to make a normal life while being named Galadriel or Moonchild … I just said that I’d enjoyed the book very much. And he said thank you. For a moment, it achieved the most basic and treasured of human communications: you are real, and therefore so am I.’ This Saturday, Sarum College plays host to a day celebrating the work of the man Terry Pratchett described as his favourite fantasy novelist. Led by Tolkien expert Stephen Tucker, the day will look in detail at The Lord of the Rings and the author’s other work, with a particular focus on his inspiration and interest in theology.

The Lord of the Rings might not immediately strike one as a text with a religious undertone. It feels a different beast – many different beasts in fact – to the work of CS Lewis, Tolkien’s friend and fellow member of the Inklings writing group. But while the Chronicles of Narnia is rich with religious symbolism, Tolkien’s fiction wears its influence with more subtlety.

I caught up with Stephen Tucker last week, and he told me how, like Terry Pratchett, he’d been a fan of Tolkien since he’d been a teenager: for Stephen, it was the 1960s BBC radio adaptation of The Hobbit that first caught his ear. He then went on to study at Oxford, where he was taught Anglo-Saxon by Christopher Tolkien, Tolkien’s son.

What caught Stephen’s imagination was ‘the story behind the story’: behind the gripping narrative was a sense of a complete world that made you want to discover more. Tolkien’s Middle Earth began with the words – he created whole languages for his characters and creatures to speak, and from this, the stories emerged.

One of the elements of the story behind the story were Tolkien’s own religious beliefs. For Stephen, Tolkien’s Catholicism is crucial in understanding how the books unfold. Middle Earth is a land, like early mythology, that is a ‘preparation for the gospel’. By which he means the underlying importance of such themes as the inevitability of human sinfulness and a determination to endure, however dark the situation.

Here, Tolkien’s own experiences come into play. As a young man, he fought in the First World War at the Somme: he then wrote The Lord of the Rings between 1937 and 1949, against the backdrop of the Second World War and the dropping of the atomic bomb. When Judy Golding came to the Salisbury Literary Festival last month, she described how her father’s novel The Lord of the Flies was partly a response to living through the 1930s. That mood and atmosphere, no doubt, infused Tolkien’s work as well.

Tolkien, it turns out, has one small but poignant link to Salisbury. In August 1973, he stopped at the Red Lion on his way to Bournemouth; when he got to his hotel, he realised he’d left his bank card in Salisbury. Tolkien had to stay with a friend instead, and it was while here that he was taken ill and died shortly afterwards.

His influence to inspire, however, continues to live on. Just this week, Amazon paid a reported $250 million to secure the global television rights for a new adaptation of Tolkien’s work. With that in the pipeline alongside Netflix’s adaptation of Terry Pratchett’s Good Omens, and with Tolkien days and Terry Pratchett exhibitions, it remains a great time to be a fantasy fan in Salisbury.

Doing Theology in Middle Earth is at Sarum College on Saturday 18 November, from 10am-4pm.