The Castle of Kingsby Oliver Potzschtranslated from the German by Anthea BellHoughton Mifflin Harcourt, 2016It's a risk that comes with liking any author of solid, enjoyable historical thrillers: the very loyalty you've shown them, multiplied a thousandfold by all their other loyal readers, will engender dreams of ambition. Suddenly those comfortable, formulaic potboilers they produced with such reassuring regularity for so many years will seem narrow and provincial; setting quirky protagonists on a prescribed road to learning who killed Count Fenwick in the refectory will suddenly pale beside the prospect of setting noble and larger-than-life protagonists on a much broader quest to understand life, the universe, and everything. When an author gets too big for his britches, one of the first things he does is march into his publisher's office, plop an 800-page manuscript on the desk (the novels in question are always tomes), and flatly declare that it's now both or neither.The problem, of course, is that the writing of formulaic potboilers no more qualifies you for the writing a “serious” 800-page historical epic than gorging at your sister's wedding buffet qualifies you for the world of competitive eating. The two actions might look similar on the surface, but they're actually radically different undertakings. Which is why most authors of historical thrillers fall flat on their faces when they attempt historical epics; for every smash success (now and forever, the go-to example will be Ken Follett's Pillars of the Earth), there are a dozen failures.German author Oliver Potzsch is a prime candidate for these dreams of grandeur. For years, he's been delighting readers all over the world with his historical thriller series The Hangman's Daughter. These novels – The Dark Monk, The Beggar King, etc. – were tightly controlled and deliciously enjoyable, as good as anything in the genre this side of CJ Sansom's Matthew Shardlake novels. They figured footprints in the snow, cloaked figures glimpsed in doorways, poisoned donuts, and other such staples of the German national experience.But as enjoyable as those books are, their international success was incubating some great whopping test of readerly patience, and in 2013 it appeared: a 650-page book called Die Burg der Konig, which now makes its appearance in English as The Castle of Kings. This is not a Hangman's Daughter novel; although they share a location, historical Germany when that region of Europe was a crazy-quilt of tiny warring kingdoms, The Castle of Kings is set nearly two centuries earlier than the murder mysteries that made Potszch so famous. The year 1524, and a Peasants' War is rampaging through Germany, giving rise to anarchy and warlords, bandits and charlatans. In the middle of some of the worst of it is Trifels Castle, and the novel centers on Agnes, the strong-willed and thoroughly Hollywood-ready unconventional daughter of the castle's castellan. Agnes likes to read, likes to argue, and is devoted to her pet falcon. She's also devoted to her geeky-inventor friend Mathis, but although he shares her feelings, their wildly different social stations mean they can only long for and bicker with each other until one or two intervening loveless spouses are eventually ground up and ejected by the plot.But just because the two can't plight their troths doesn't mean they don't want to, and in the meantime, Mathis's skill as a blacksmith and Agnes's value as a matrimonial bargaining chip thrust both of them into a series of plot-twists, each more outlandish than the last (there are developments especially in the last third of the book that really do feel like Potzsch responding to dares from his friends). The world around them is in the midst of social upheaval, which our author signals with all the subtlety of a hurled textbook:

“Down with those damn tithes,” yelled someone else, not far from Mathis, a thin old man leaning on a stick. “The bishop and the duke are fat and healthy, and here you go hanging children who don't know where their next meal is coming from. What kind of world is this?”

The book takes one of its many defiantly strange turns when Agnes's pet falcon returns to her one day bearing a mystic ring that, upon consultation with the appropriate sources of exposition, turns out to have a rumored connection to one of the most iconic Germans of all – the mighty Barbarossa:

The name seemed to hang in the air while Agnes leaned back thoughtfully. Emperor Barbarossa featured in many of the stories she had devoured up here in the library of Trifels Castle. He had been the first of the famous emperors from the Hohenstaufen family who had ruled the German Empire for several generations about four hundred years ago. Barbarossa had been tall and strong, and his red beard was legendary. At a great old age he was drowned in the Saleph River while on Crusade, but there was a story that he was still sleeping under the Trifels. It was a legend that had probably arisen because, after the Hohenstaufens, there had been a time without an emperor when lawlessness prevailed.

Agnes and Mathis have many, many adventures in the course of the hundreds of pages that follow, and so too does the rest of Potzsch's cast of hundreds. Readers who crave thickly-crowded narratives will have plenty to satisfy them in these pages. But the britches curse – or at least a mild version of it – does unfortunately strike The Castle of Kings. There are turgid stretches, something that never happened in the murder mysteries, and the characters are too busy representing history to ever really live it, with the result that great stretches of the book feel flat, despite the generous and sometimes playful elements of fantasy the author throws in from time to time. There was hardly a moment while reading any of the Hangman's Daughter books when a reader would have been tempted to put the story aside and do something else for a while, but moments like that happen far too often in this big change-of-pace book. Of course that's the risk you run.