When I tell people I write about medieval conspiracies, they usually think I mean The Da Vinci Code—secret societies, hidden bloodlines, Knights Templar protecting the Holy Grail.
The real medieval conspiracies were stranger. And most of them actually happened.
Here are five that informed the world of The Aethelred Cipher—not because I copied them, but because reality kept outpacing what I thought was plausible fiction.
1. The Templar Arrests: A Coordinated Strike Across an Entire Country
October 13, 1307.
On a single Friday morning, agents of King Philip IV of France simultaneously arrested every Knight Templar in the country. Thousands of men, in hundreds of locations, seized in a coordinated operation that had been planned in absolute secrecy for months.
The logistics alone are staggering. In an era without telephones, without telegraph, without any communication faster than a man on horseback, Philip's agents coordinated a nationwide strike with the precision of a modern special forces operation. Sealed letters had been distributed weeks in advance, with instructions not to open them until the designated date.
The charges against the Templars were almost certainly fabricated—heresy, idol worship, obscene rituals. Philip owed the Templars enormous debts, and the arrest conveniently eliminated his creditors while allowing him to seize their assets.
But the conspiracy that interests me isn't Philip's plot against the Templars. It's the Templars themselves.
By 1307, the Knights Templar had spent two centuries building one of the most sophisticated financial networks in medieval Europe. They invented modern banking—deposit accounts, letters of credit, international fund transfers. A pilgrim could deposit money in London and withdraw it in Jerusalem.
They also maintained a network of commanderies (local houses) spanning every kingdom in Christendom, communicating through sealed letters carried by their own couriers, answering to no authority except the Pope himself.
A multinational financial network, operating across borders, answering to no king, communicating in codes. Two hundred years of institutional continuity. And it took a coordinated strike across an entire country to bring them down.
What this taught me for the novel: Multinational networks operating across medieval borders weren't just possible—they existed. The infrastructure for the Order in The Aethelred Cipher is modeled on organizations like the Templars, who demonstrated that coordinated transnational power was achievable with medieval technology.
2. The Cadaver Synod: When a Dead Pope Was Put on Trial
January 897, Rome.
Pope Stephen VI ordered the body of his predecessor, Pope Formosus, exhumed from its grave. The rotting corpse—dead for seven months—was dressed in papal vestments, propped on a throne in the Lateran Palace, and put on trial for perjury, violation of canon law, and illegally serving as Pope.
A teenage deacon was appointed to speak for the corpse.
Formosus was found guilty. His papal acts were declared void. The three fingers of his right hand (used for papal blessings) were cut off. His body was dragged through the streets and thrown into the Tiber.
This wasn't madness. It was politics.
Formosus had belonged to one political faction within the Church; Stephen to another. By retroactively annulling Formosus's papacy, Stephen invalidated every appointment Formosus had made—every bishop, every abbot, every legal document signed under his authority. It was a systematic purge disguised as a trial, targeting not a man (he was dead) but the institutional legacy he'd left behind.
The power play failed. Public revulsion led to Stephen's overthrow and murder within the year. But the Cadaver Synod revealed something important about medieval power: institutions could be weaponized. The machinery of legal and religious authority—trials, annulments, excommunications—could be turned against anyone, living or dead, if you controlled the levers.
What this taught me for the novel: The Church in The Aethelred Cipher isn't a monolithic good or evil institution. It's a machine that different factions fight to control. The Order doesn't need to be the Church—they just need to influence who sits in which chair.
3. The Venetian Intelligence Service: Spies in Every Port
1200-1500, The Republic of Venice.
Venice operated the most sophisticated intelligence service in medieval Europe. The Council of Ten—a secretive governing body established in 1310—maintained a network of spies, informants, and agents that reached into every major port and capital in the Mediterranean.
They employed cryptographic systems that weren't broken until modern times. They intercepted diplomatic mail. They paid informants in foreign courts. They maintained files on the political and commercial activities of rival states that would be recognizable to any modern intelligence analyst.
The system worked because Venice was a commercial republic—a city-state whose survival depended on information. Knowing which trade routes were safe, which cities were at war, which rulers were stable and which were about to be overthrown—this was intelligence in the commercial sense. Life and death for a city that lived by trade.
But Venice's intelligence gathering went beyond commerce. The Council of Ten tracked bloodlines. Not in the eugenic sense—but in the political sense. They maintained genealogical records of noble families across Europe, tracking marriages, inheritances, and political alliances. This information was used to predict succession crises, identify potential allies, and exploit rivalries.
A commercial republic. Tracking bloodlines. Maintaining secret archives. Employing a network of agents across Christendom. Communicating in cipher.
I didn't have to invent the Order's intelligence capabilities. Venice had already built the prototype.
What this taught me for the novel: The Order's ability to maintain records across centuries and monitor families across Europe isn't a fantasy. Venice did it for three centuries with medieval technology. The only fictional element is the purpose—breeding rather than politics.
4. The Flagellant Movement: A Conspiracy of Despair
1348-1349, Europe.
During the Black Death, groups of men marched from town to town, publicly whipping themselves with leather straps embedded with iron spikes. They chanted hymns, wore white robes marked with red crosses, and performed elaborate rituals of self-punishment in town squares.
This sounds like spontaneous religious fervor—and partly it was. But the Flagellant movement was also organized, hierarchical, and increasingly political.
Flagellant groups were led by "masters" who controlled membership, dictated ritual, and directed the groups' movements from city to city. They followed planned routes. They carried sealed documents that supposedly authorized their activities. They developed their own theology—one that increasingly challenged Church authority.
Most disturbing: wherever Flagellant groups appeared, pogroms against Jewish communities followed. The correlation was so consistent that historians believe it was deliberate. Flagellant masters directed mob violence against Jewish quarters as part of their program, using plague terror as a tool for social upheaval.
Pope Clement VI banned the Flagellants in October 1349. Many ignored him. The movement had developed its own institutional momentum—a distributed network of charismatic leaders, coordinating across borders, using religious ritual to organize collective action.
It was a conspiracy of the desperate. And it demonstrated something the Order in my novel understands perfectly: catastrophe creates opportunity. When existing institutions fail—when the Church can't explain the plague, when physicians can't treat it, when governments can't stop it—people are desperate for someone who can offer meaning. And whoever fills that void gains power.
What this taught me for the novel: The Black Death in The Aethelred Cipher isn't just a backdrop. It's an active force that destabilizes existing power structures and creates opportunities for both the Order and the resistance. Thomas doesn't just fight the Order during the plague—he fights within a power vacuum that the plague creates.
5. The Papal Banking Conspiracy: How Monks Invented Finance
1200-1400, Christendom.
Medieval Christianity had a problem with money. Usury—lending at interest—was a mortal sin. The Bible was explicit. Canon law was clear. Charging interest on loans could damn your immortal soul.
This was inconvenient, because the medieval economy ran on credit.
The solution was one of history's great institutional conspiracies: the Church developed a series of legal fictions that allowed banking to function while technically avoiding the sin of usury.
The bill of exchange: A merchant in Florence gives money to a banker. The banker's agent in London pays the equivalent to the merchant's partner, minus a "fee for service" that is absolutely not interest because it's compensation for the trouble of currency exchange.
The census contract: I sell you the right to future income from my land. You pay me now; I pay you annually. This is absolutely not a loan with interest—it's an investment in agricultural production.
The triple contract: A partnership where one partner is guaranteed a fixed return. This is absolutely not a loan with interest—it's a commercial partnership that happens to have a guaranteed minimum yield.
The Medici bank, the Bardi, the Peruzzi—these vast financial houses were built on legal fictions that everyone understood and no one acknowledged. The Church collected fees from the bankers. The bankers collected fees from the merchants. And the entire system functioned because a conspiracy of silence maintained the fiction that no one was doing what everyone was obviously doing.
What this taught me for the novel: Medieval institutions were capable of extraordinary collective deception—not through malice, but through the human capacity to build systems that everyone participates in and no one examines too closely. The Order's breeding program in The Aethelred Cipher works the same way. Individual monks keep records. Individual monasteries track families. No one outside the coordinating centers sees the complete picture, and those inside the system have been trained not to ask.
The Pattern Behind the Conspiracies
What connects these five real conspiracies?
Institutional infrastructure: Every conspiracy used existing institutions—the Church, trade networks, monastic orders—as cover for activities those institutions weren't designed for.
Information asymmetry: The conspirators' advantage was always knowledge. Knowing what others didn't—trade routes, political alliances, financial flows, disease patterns—created power.
Transnational coordination: Every conspiracy operated across medieval borders, using communication networks that predated the conspiracy itself.
Plausible deniability: The most successful conspiracies (Venetian intelligence, papal banking) survived because they maintained the fiction that nothing unusual was happening.
Generational continuity: The most durable conspiracies (Templars, Venetian intelligence) lasted centuries because they were embedded in institutions that outlived individual participants.
These are exactly the principles behind the Order in The Aethelred Cipher. The fictional conspiracy is built on a foundation of real ones—because the real medieval world was stranger, more capable, and more dangerous than we give it credit for.