From time to time, Mosse stepped out of her narration of the historical events that form the groundwork of her best-selling novel Labyrinth to talk, in her terms, about the life story of how a novel comes into being. She took us back to 1989 when she first found herself in the shadow of the walls of Carcassonne, a medieval city in the Languedoc region of France, and of how she immediately felt at home there.

Then she drew us into a visit she paid to Montségur in 1992, high up in the Pyrenees. From there, she climbed above the cloud cover to reach the citadel, a fortress that had served as a defence for a medieval Christian sect, the Cathars. It was here that she discerned, in an almost material way, the appearance of Alaïs, a central character of the book. For Mosse, a writer of historical fiction is something of a receptacle for ideas, these ideas often coming from places, and whose task is to turn these into imaginative fiction, using research to underpin them.

This sense of place ran throughout the show, and Mosse’s telling of events in the Languedoc during the 11th, 12th and 13th centuries was gripping. Her depiction of the brutality of the crusade against the Cathars, initiated by the Catholic Church and largely executed by government troops, was vivid, and her knowledge of the history of the time encyclopaedic.

But Mosse was mindful throughout the show of taking us back to the role of the creative writer in interpreting history. We learned from her how she used her modern-day character of Alice to look back at events and uncover the secrets of times long gone. And she talked about some of her influences, including a school visit to Chartres Cathedral, where she first came across the symbol of the labyrinth in its stone floor.

For Mosse, the core of her novel Labyrinth is the theme of standing up for your principles, and of being witness to the truth. There was more than one, very timely, occasion when her presentation took a swipe at the current political climate within the world.

A natural presenter, and skilled in holding people’s attention, Mosse managed her audience with an easy wit, although there were times when we may have felt a little over-managed.

Unlocking the Secrets of the Labyrinth celebrates the 20th anniversary of the book Labyrinth. It also provides a golden opportunity for Mosse to sell the book to those who haven’t read it. But, let’s face it, today’s authors have to be promoters as well as creative writers and she is pretty good at that too.