When the Knights Templar were fighting in the Holy Land and running their operations across Europe – they might just as easily die of plague as being killed in battle. So, which plagues were likely to kill a knight? And just how dreadful were these incurable diseases? You’re a ghoulish lot so you want to know…don’t you?
Let’s look at the plagues you could have contracted in the Templar period:
Bubonic plague: Bubonic plague is caused by the bacterium Yersinia pestis, which is primarily transmitted to humans through the bite of infected fleas, usually those that live on rodents. These might be rats, mice, and voles. As we’re seeing in our own time, the proximity of humans to animals was a major cause of transmission. Bubonic plague could also be contracted by handling infected animals or by inhaling respiratory droplets from someone with pneumonic plague.
The symptoms are pretty gross and include swollen and tender lymph nodes (buboes), high fever, nausea, vomiting, diarrhoea, abdominal pain, and ulcers around the initial flea bite. It took between 48 hours and a week for the plague to take hold after initial exposure to the bacteria. The infected person would then have to be locked into their abode with a cross painted on the door. They were expected to remain there until they died.
There had been outbreaks of bubonic plague going back to the dawn of civilisation. Researchers have found DNA evidence of Yersinia pestis in human remains dating back to the Bronze Age. In the Byzantine Empire, during the sixth century CE, the city of Constantinople was ravaged during the Plague of Justinian (named after the emperor). One account has the bodies being dumped into the many towers that punctuated the long walls around the city. The stench must have been revolting.
The most infamous outbreak of bubonic plague was The Black Death – which began in 1346, over thirty years after the Templars were crushed. At least they couldn’t be blamed for that! It killed about fifty million people in Europe, which was up to half the population. Experts are still trying to estimate the death toll, which was on a vast scale.
The Black Death originated in Central Asia, near Lake Issyk-Kul in modern-day Kyrgyzstan. It spread along trading routes, arriving in southern Italy before heading on to every city on the continent.
Smallpox: Thanks to vaccines, smallpox has now been completely eradicated. But for three thousand years, it was a major killer. One of the earliest reported examples was the Antonine Plague that devastated the Roman Empire between 165 and 180 CE.
Smallpox was caused by the Variola virus, a member of the Poxviridae family. The disease began with a high fever, fatigue, and back pain, followed by a characteristic rash that started as small bumps, filled with fluid, and eventually developed into pus-filled blisters, or “pocks”. Smallpox was a highly contagious and deadly disease, with a mortality rate of around 30%.
Survivors often suffered from permanent scars, and some were left blind. Smallpox was a major cause of death and suffering throughout history, affecting people of all ages and social classes. Its spread tended to coincide with invasions that brought disease with the armies. So it’s very likely that the Crusades brought smallpox into European communities from the Middle East – and vice versa.
St Anthony’s Fire: Eating rye infected with a fungus gave rise to this hideous condition. The fungus was Claviceps purpurea and the alkaloids it contained had devastating consequences – both physical and psychological. It was common in the Templar period, especially in regions where rye was a staple food, leading to outbreaks of the disease.
Once infected, the sufferer experienced a burning pain in the limbs, gangrene (tissue death) in the extremities, and convulsions. But that was followed by hallucinations and mania. This was like the worst acid trip imaginable. People reported having visions and, needless to say, in the Middle Ages – these experiences might be taken at face value. Some have speculated whether certain holy people and saints who were visited by angels were in fact in the grip of St Anthony’s Fire.
Leprosy: Nothing terrified the average medieval villager more than hearing about a leper living in their midst. There was even a special mass, said by the local priest, where the leper would be ceremoniously cast out of the community. Should they wish to ever hear mass in a church again, they had to watch the service through a “squint” in the church wall. That was a hole that allowed them to join mass from outside the building.
Special leper hospitals were built beyond the walls of towns or cities. They offered shelter, basic medical care, and in some cases, medication and treatment for the seriously ill. They were sometimes named after Saint Giles – the patron saint of the disabled. In London today, you can still visit the church of St Giles in the Fields, near Tottenham Court Road. It’s now in a very busy part of London’s west end. But in the Templar period, it was literally in the fields – and it was a leper hospital.
If you would like to know more about the Knights Templar, then get your hands on a copy of my book: The Knights Templar – History & Mystery. Published by Pen & Sword and available on Amazon, Waterstones, Barnes & Noble, and WHSmith. Don’t miss out on your copy!

