The Pretender by Jo Harkin
This has been likened to the historical fiction of writers like Hilary Mantel and Maggie O’Farrell, and I have to say that I can see it reaching the level of popularity and acclaim that books by those authors did—at least partially because it’s so messy.
So let’s get to the mess: in 1480, John Collan is attending to his peasant duties (which involve a goat) when he’s approached by a well-dressed stranger who tells him that his whole life has been a lie. He’s not John at all, but Lambert Simnel, son of the long-dead Duke of Clarence, and sent away because the Duke’s brother, Richard III, liked to unalive his nephews. Well, now that his true identity has been revealed, John-now-Simnel is sent to court in Ireland, learns etiquette, and even meets the delightfully manipulative—and occasionally murderous—Joan, the daughter of his Irish patrons. In a way, the two aren’t so different—she can either go to the convent or to the wedding altar, and he can be king or die. That’s why they come together to plot and scheme, changing the course of England forever.