Why I Wrote... Against the Devil's Men
- cepmurphywrites
- 3 days ago
- 8 min read
By Alexander Rooksmoor

Sea Lion Press has published over a hundred alternate history books so far... but what leads an author to pick the point of divergence they picked and tell the story they told? This time, we hear from Alexander Rooksmoor about his tale of a Mongol invasion of Western Europe...
My prime inspiration for 'Against the Devil's Men' (2019) came from reading a non-fiction book, in this case very specifically 'The Devil's Horsemen' (1979; revised 2003) by James Chambers. I had bought a hardback copy of this in the 1980s, partly inspired by the cover but also the map it contained. This stretched across much of Asia, showing a perspective on the world pretty different from the ones we tend to see. Having read this book, I was struck by how different the world might have been if in 1242, the Mongol forces had not called off their advance through Eastern Europe to return to East Asia to deal with the consequences of the death of Ögedei Khan.
Ögedei had successfully continued the rapid expansion of the Mongol empire by his father, Genghis Khan. In 1241 alone, the Mongols had defeated Polish forces at Legnica and Hungarian forces at Mohi/Muhi. There appeared nothing that the Europeans possessed which could defeat the Mongol war machine. The battle tactics of the Mongol horse archers and the range their bows could reach made it very hard for any other forces of the time to oppose them. While horse archers were the core of the Mongol force, the armies also assimilated military approaches from those they defeated. For example, Chinese siege equipment was to benefit the Mongols in conquering European towns.
Europe had been periodically invaded by horse-borne steppe tribes from even before the Roman Empire was established. We can see this with the Scythians, the Alans, the Avars, the Huns, the Goths, the Cumans, the Turkomens, the Pechenegs, among many other invading peoples. Some, notably the Magyars and the Bulgars, became assimilated into Europe and themselves faced subsequent invasions from central Asia. Many of these invaders, notably the Huns, became a by-word for destruction of civilisation. However, none of these other peoples managed the scale or the brutality of the Mongols.
In 1258, the destruction of the city of Baghdad by the Mongol army shows the extent they would go to if a town resisted. The sacking went on for a week and at least 200,000 citizens were killed, perhaps many more. Subsequent disease raised the death toll. Due to Mongol aversion to exposing the blood of execution victims to the sky, the Mongols adopted grim methods of killing elite prisoners. Following the Battle of the Kalka River in 1223, the defeated Rus nobles were sealed into a platform to suffocate while Mongol commanders sat above them dining. The Caliph at Baghdad, Al-Musta’sim, was executed by being wrapped in a carpet and trampled by horses. Thus, we can estimate what we might have expected to see if the Mongols had persisted westwards and reached the regions that these days form parts of Italy and France. In portraying the areas wrecked by their advance, I was influenced by 'The Gate of Worlds' (1967) by Robert Silverberg and 'The Years of Rice and Salt' (2002) by Kim Stanley Robinson. These two novels started with a Europe that has suffered much more from the Black Death. Given the scale of massacres, the flight of refugees, and destruction by the Mongols, I envisaged similar wastelands, notably in northern Italy which was one of the most urbanised areas of Europe at the time.
As happens with many of my novels, I had started with analysis of the situation as a chapter in 'On Other Fields' (2014). Then I wrote a short story 'Facing the Devil' included in the anthology 'Déviation: What If? Stories of the French' (2015) before turning to my novel. 'Facing the Devil' is set slightly later, in 1272, perhaps in a different timeline, when the Mongols are envisaged as having reached northern France. However, for 'Against the Devil's Men', set in 1267, I focus on a slightly earlier period to consider what steps Western Europeans and especially the Papacy might have done to organise a defence on the modern Franco-Italian border. To some degree, the Alps, the terrain of Italy and the hedgerows of northern France would have made further progress for the Mongols harder than they had experienced before in Europe. Even so, the city of Rome in my novel is on the frontline of the Mongol invasion down the Italian peninsula and the Papacy has relocated to Aragon.
I envisaged that in this context, effectively an extended crusade would have been declared within Europe. This was not exceptional as there had been the crusade in 1209-29 against the Cathars in southern France; the crusade against Bogomil heretics in Bulgaria in 1234 and 1252; and against the Bosnian heretics in 1235 and 1241. Of course, the Reconquista against Muslim states in Iberia was ongoing, 722–1492. The Mongols were a strong threat to Arab states in the Middle East and could have threatened those of North Africa too. Thus, in my novel, on the principle of ‘the enemy of my enemy could be a friend’ a truce has been struck by the Papacy with the Emirate of Cordoba. Partly as a result, I imagined that the crusading orders, the best known being the Templars and the Hospitallers, but also a range in Spain and Portugal such as the Order of Calatrava and the Order of Santiago, would now fight against the Mongols.
I did feel that after the repeated failures against the Mongols, new military approaches would be adopted such as European 'turcopole' archer calvary as used in the Crusade. In addition, that rather than simply relying on knights and men-at-arms, the Church and towns would seek to mobilise the entire population in defence. In some ways this would be a practical step but also be seen as leading townspeople away from heresies. Walled towns were common anyway, but in this novel their defences are strengthened and effective warning systems put in place. The character of Brother Cataldo is portrayed as a kind of inspector constantly checking towns’ defences.
The arrival of steppe tribes in Europe typically promoted fears of the "end of times". The Tatars, another steppe group that migrated westwards, were typically called "Tartars" in reference to the Roman hellish underworld regions of Tartary. In my novel such fears of an apocalypse, as would later happen with the Black Death, has led to the reappearance of "millennial" groups such as Flagellants. I have also included a fictional group the “Edenites”. With the turning of northern Italian towns and cities into ruins, some people have felt a kind of restoration of Eden is on its way. As in our own times, such cults and the communes they build have become commonplace.
The Cathars also feature in the novel. They followed a dualistic pescatarian, celibate religion which had male and female priests. They saw only light and the soul as being created by God and the rest of existence as something devilish. In our world they were massacred in the early 13th Century, but I have envisaged them returning due to this millennial tendency. I had read ‘Montaillou’ (1975) by Emmanuel Le Roy Ladurie, a non-fiction book about a Cathar village that had been a mainstream bestseller in Britain when published in English in 1978 and the magic realist novel ‘Labyrinth’ (2005) by Kate Mosse, which is partly set among medieval Cathars.
Once I had the setting in place, I began to look at what characters would allow me both to show this context effectively and provide the basis of a gripping story. I also aimed to draw attention to particular groups that I felt would be interesting for readers to read about. Brother Cataldo is a Trinitarian friar, a rather forgotten religious order of the time. I also wanted to have a character from a people similar to the Mongols and familiar with their ways of warfare, but with an interest in defending western Europe, hence having a Cuman character in Captain Braçayda “Barc” Ulas. The Cumans had been one of the steppe peoples who had moved West of the Black Sea, even at the time of the Romans. In the 11th and 12th Centuries they advanced westwards fighting Rus', Hungary and Poland. However, with the Mongol invasion they allied with the Rus' princes, but following Mongol advances in the late 1230s and a final defeat in 1241 they fled to the Hungarian plain where they were received ambivalently by the Magyars.
Another character arose from knowing that some Byzantine noblewomen, usually illegitimate ones, were married off to Mongol khans. Maria Palaiologina and Epuhrosyne Palaiologina are two we know about. The misery of a woman from a comfortable Byzantine house sent to live in a Mongol yurt seemed to be neglected by blithe commentary on such marriages. I envisaged, with the Mongols moving westwards, further such forced marriages would have occurred from other European stated and the women and the children they bore might have loathed their circumstances. Sister Aurea is a mixed-race Italian/Mongol woman who hates what her father’s people have done. She has become a Mercedarian, an order which, unlike the Dominicans or Benedictines, does not get much mention. They were sworn to help Christians who had been imprisoned by non-believers, even offering themselves in the prisoners’ place.
With all the characters I sought to have them true to the views that people of the time and in their roles would have held to. This can be tough for any writer of historical fiction, including alternate history, as it means readers having to go along with characters whose values that maybe antithetical to those they hold. I was aware that many modern readers would be more sympathetic to the views of the Cathars and the Edenites than they would be to those of religious orders of the Thirteenth Century, though I did have one reader who very much lauded the methods of the Mongols of the time.
Another element to include was the Mongol relationship with Venice and Genoa. I went with attitudes of other Europeans of the time which saw the Venetians as traitorous to Christendom, in part through detouring the 4th Crusade to smash up Constantinople in 1204. Venice signed a trade treaty with the Mongols in 1221 before they had really reached Europe. Genoa was the prime trading rival of Venice, so it tended to end up on the “other side” in conflicts and whereas Venice took territory from the Byzantine Empire, Genoa supported the empire and received concessions at Black Sea towns. However, with the advance of the Mongols, I envisaged that the Genoese would have also had to come to a deal with the invaders in order to save their trading empire.
With all this in place, I just needed a way in which a group of adventurers could strike back against the Mongols. As typical military methods had failed, it seemed the Church would turn to things like biological warfare. By the Thirteenth Century, making use of fungus to poison supplies and driving or throwing diseased people in among the enemy had been used for thousands of years. Thus, I explored diseases among horses, the essential vehicle for Mongol expansion, that were slow to kill, allowing infection to be spread.
With all this in place, the nature of the characters and where they had to go, took over and propelled the narrative of the novel.