Exactly 566 years ago today, 29 May 1453, Constantinople fell to the Ottoman Turks after a 53-day siege. The Byzantine Empire had been effectively dead for at least a century, but its splendid capital survived behind massive, impenetrable walls. The young Ottoman sultan, Mehmed II, whose empire by that time already stretched from the Danube to Armenia, had decided at last to add the magnificent jewel to his crown and assembled a massive host for the siege. For several months before his army appeared before the walls, the entire city was gripped by dread anticipation of what most suspected would be their doom. This is the setting for Peter Sandham’s first novel, Porphyry and Ash.

Imagine a ship, John, an old trading balinger that’s done the run from Genoa to Cyprus for generations. It’s seen out many a storm in its day, but time has left its timbers rotten and vulnerable. Now, you could sign on with its crew and maybe you make it to port and earn your coin, but maybe the next storm is bigger and splits the rotten hull and the sea pours in on you. This sort of opportunity is best left to the foolhardy. Better to sit on the harbourside and wait for another boat.

Such is the advice an old Genoese mariner gives to John Grant, a Scottish mercenary who is the novel’s protagonist. The year is 1452, and John has just arrived in Constantinople, the rickety ship to which he is about to lash his fortune. We see the dilapidated capital of the once-grand Byzantine Empire through John’s eyes, a Westerner raised on tales of its splendor. The ramshackle houses and crumbling churches are a sign of just how far the city has declined over the centuries from the height of its glory.

It is not just the physical decay, but the moral decay of the city that shocks the new arrival. While the siege would eventually inspire many noble acts of bravery, the cynical willingness to sell out one’s neighbor for some short-term gain was depressingly common. The question implied by the old Genoese’s advice recurs throughout the novel: why would anyone fight for such a lost cause? For John, it is exactly the hopelessness of Constantinople’s position that draws him. Having wandered the world practicing a sordid profession, he sees the chance to expiate his sins by dying for a noble cause.

But moral abstractions are by themselves rarely sufficient reason to fight, and the last days of Byzantium were moreover far from morally pure. Sandham shows us just how complicated is the world that John stumbles into, dominated by religious controversy, Venetian and Genoese scheming, dynastic politics, and myriad petty jealousies. One of the novel’s great strengths is how it shows just how many world-spanning questions converged in Constantinople at that time. On several occasions, I found myself looking up some small detail that turned out to have a large and interesting story behind it.

Far from descending into historical pedantry, however, the action keeps pace with the gradual unveiling of this strange world. This comes across particularly well in lively scenes of group dialogue. Sandham deftly uses the din of a full room and the meanderings of mixed company’s conversation to tease out backstories. Passing comments and retorts avoid tedious exposition of the complicated events which provide a faithful historical backdrop to the action. Indeed, the only part of the story that strains credulity is the part that takes the greatest license, the love plot between John and a Byzantine princess. Even here, though, the author gives enough attention to court politics and the characters’ psychological complexity to make it interesting—it is something more than the stock romance plot of a beautiful princess swooning over a handsome barbarian.

Yet for all that subtle plots and complex events dominate the plot, they are overwhelmed by the siege of Constantinople itself. Like the Turkish cannonballs shattering the ancient masonry of the Theodosian walls, the hard reality of the siege destroys everyone’s illusions and pretensions. Sandham evokes the nerve-jangling tedium of daily life under constant artillery bombardment, interspersed with the sheer terror of actual combat. The grueling weeks of siege warfare exacerbate the tensions of the various subplots, leading up to the final assault which brings everything to its culmination.

Porphyry and Ash stands on its own as several different books: an introduction to Byzantine history for the complete novice, a faithful and detailed depiction for the Byzantine enthusiast, or an absorbing, well-paced adventure for those who want nothing more. It is the first in what promises to be a fun and compelling series of novels, beginning with the close of the Byzantine era and progressing through the tumultuous events that follow in its wake.

You can purchase Porphyry and Ash on Amazon. The author also has a great Twitter feed in which, among other things, he discusses a lot of background detail of the book: @HKSandham.