One day in 1484, strange men arrive at the Oxfordshire farm where 10-year-old John Collan lives. They’ve come to carry him away to a new life, for he is not, after all, the farmer’s son; in fact, he’s Edward Plantagenet, Earl of Warwick, spirited away in infancy to keep him safe ahead of the day he might return to claim the throne of England. That day is now in sight. He can’t call himself John any more, but he can’t yet be announced as Edward, Earl of Warwick. In the meantime he’ll be given a third name: Lambert Simnel.

Over the course of this fantastically accomplished novel, the many-named boy will travel from Oxford to Burgundy then Ireland, and at last into the paranoid and double-crossing heart of Henry VII’s court. The tail end of the Wars of the Roses – with Richard III’s crown snatched from the mud of Bosworth by Henry Tudor – is a foment of plot and counter-plot, and our hero spends his adolescence being passed around scheming factions who go so far as to hold a coronation for him. What a painful life this is for a boy “so grateful for any amount of love” as he falls in and out of favour, uncertain of his own parentage, gaining and losing relatives as their interest turns to other plots and other pretenders.

He’s heard stories of changelings, but at least those strange children come with the clarity of a straight swap: Simnel is all his past selves, and none of them. He thinks of John, the sweetly priggish little boy from the farm, who loves mystery plays and football and fairy stories, “bricked up like an anchorite” inside his new self. One character describes him as a changeling in reverse, “for changelings are dark and wicked things and Edward a fair prince” – but once he’s demoted back to Simnel and becomes embroiled in the machinations of the Tudor court, those “dark and wicked” elements are revealed as inextricable from the “fair prince”.

At least he has the consolation of an education. Hothoused in the ways of nobility, our hero “[eats] up every learning he’s been given like a chicken after grasshoppers”. His intellectual world is communicated impeccably and with purpose. Simnel rejoices in books, begs for them, is “astonied”, outraged and aroused by their contents. The Pretender is scattered with fine knobbly period language (“dole”, “maigre”, “puissant”, “wroth”) and witty dialogue, and this stylish delivery brings with it considerable substance. Simnel’s reading of Chaucer, Dante, Malory, John Gower and John Lydgate alongside classical works of Boethius, Juvenal, Horace, Ovid and Apuleius isn’t included simply to pay lip service to historical research. There’s a deep love for literature here, and a desire to showcase the formation of the late-medieval mind, which elevates The Pretender above other novels about this period. Simnel, wrestling with all manner of rhetorical devices, discovers bocardo syllogism: “All kings are of noble birth. You become a king. You are of noble birth.”

In interludes, he attempts to write about himself. He tries fairytales and romances, but when attempting satire he comes to the realisation that if “satire is written by the noble, in service of the social order”, then as upstart pretender to the throne, “he’s exactly the thing they’re complaining about”. Delving into history books, “the fragility of the past horrifies him”. It turns out facts are far more mutable than he’d imagined: “some dead historians have lied, or guessed, and now nobody knows what’s true”. When it comes to reading autobiography, he finds authors “making an argument for their selves”, but by this time he has no self of his own to argue for. In fact, he’s already signed a prepared confession renouncing his alleged identity. Is he now complicit in his own disappearance?

There are few historical eras as passionately disputed as the Wars of the Roses. Much ink and emotion has been spilt in debate of its perceived heroes and villains. Harkin’s version of Simnel and his world, therefore, will not necessarily please every reader – but this is a feature rather than a bug. The Pretender is a novel about uncertainty. “Only kings write history”, perhaps, but when those kings are so busy deposing one another, “history is written in wax”. This doesn’t happen in the rustling domain of documents preserved or burned, copied out or left to rot: John/Edward/Simnel shows us what happens when it’s your own life being revised and rewritten even as you live it. A traditional Bildungsroman concerns an individual’s process of becoming. What is the name for a tale of unravelling?

“In a few hundred years,” our hero says, “Richard [III] will be a hunchback and I’ll be a scoundrel.” This bold, brilliant and deeply compassionate treatment restores a life to Simnel. Was it the life he lived? None of us will ever know.