Spin doctors, we like to imagine, are a modern curse. I don’t agree. As long as there has been civilisation, rulers have tried to use wordcraft and images, monumental architecture and pageantry, to mould the attitudes of their peoples.

In my historical novel, A Prize of Sovereigns, currently being serialised, Guillem Marti Moles is a medieval spin doctor. He’s probably the character I had most fun writing. A charming rogue, amoral and with an eye to the main chance, he rises from itinerant storyteller to the dizzying and perilous position of Royal Bard.

In this week’s instalment, Guillem demonstrates the power of the printing press to the Chancellor, Terpanijan.

Guillem continued, ‘The truth is what people believe it to be. And with a thousand copies of my pamphlet in circulation for every hand-written account, people will believe what we tell them.’

Now Terpanijan laughed too. ‘And people say I am cunning.’ He shook his head. ‘With your block copying, it will be possible for a man to shape the thoughts of a nation.’

The trial of Marta, Maid of Mewwald on charges of witchcraft and heresy of event is drawing to a close. Guillem has written a pamphlet, The King and the Witch, intended to destroy Marta’s reputation, so that her nation will no longer follow her in resisting conquest. Marta is a Joan of Arc figure. In fact, much of the trial is taken from a real account of Joan of Arc’s trial.

Men like Guillem have, for millennia, written the words that inspire their nations to follow generals, exalt rulers, and condemn enemies.

Remember, for example, of how Alfred Lord Tennyson transformed into inspiring heroism the disastrous Crimean War blunder of the Charge of the Light Brigade towards the Russian cannons:

Half a league, half a league,
Half a league onward,
All in the valley of Death
Rode the six hundred.

Or consider of the Egyptian Pharaoh, Akhenaten. His power struggle with the temple priests of Karnak led to the brief erasing of Egypt’s ancient gods, and their replacement by the one state god, Aten. And don’t forget the priesthood’s terrible revenge, still visible in the statuary of that period with the face of Akhenaten erased.

None of this means that the ancient spin doctors necessarily supposed they were telling the truth. Guillem’s true sympathies lie more in the tavern than in the palace, and he secretly writes a true account of the Maid. But it does mean the stories that came down to us through the ages were shaped by the power struggles and ambitions of their rich patrons.

Joseph Campbell claimed that all stories are variants of a single story, often referred to as “the hero’s journey”. Campbell’s schema, which was slavishly copied by George Lucas in crafting the first Star Wars movie, has 12 stages.

But critics say this is evidence, not of the impossibility of alternative stories, but of powerful patrons wanting tales that cast them in the best light.

Guillem’s secret treason is testimony to the existence of other narratives.