The summer of 1665 was brutally hot. In the cramped, timber-framed houses of London, the air felt thick enough to choke on. People weren’t just sweating from the heat, though. They were terrified. By June, a handful of deaths in the parish of St. Giles-in-the-Fields had turned into a steady stream of "bills of mortality" that the city couldn't ignore. This wasn't just a bad flu season. The 1665 plague in London—the Great Plague—had arrived, and it was about to dismantle the city's social fabric in less than a year.
Most people think of the plague as a medieval thing. It’s not. While the Black Death of the 1340s is more famous globally, the 1665 outbreak was a sophisticated, urban disaster that hit a maturing, early-modern city. It killed roughly 100,000 people. That was a quarter of London’s population gone in months. Gone.
Why the 1665 Plague in London Was a Perfect Storm
London was a disaster waiting to happen. You have to understand the geography. The city was bursting at the seams, with people living in "tenements" that were basically death traps. Hygiene? Non-existent. People threw waste into the middle of the street, which they called "the kennel."
It’s easy to blame the rats. Everyone does. But the real culprit was the Xenopsylla cheopis—the flea that lived on the black rat (Rattus rattus). When the rats started dying off from the bacteria Yersinia pestis, the fleas needed a new host. Humans were the next best thing.
Samuel Pepys, whose diary provides the most visceral account of this period, noted the growing unease in April and May. He saw the red crosses appearing on doors. He saw the "Lord have mercy upon us" signs. It started slow, then it hit like a freight train. By September, 7,000 people were dying every single week. Imagine that. A city the size of 17th-century London losing 1,000 people a day. The bells for the dead rang so often that they eventually just stopped ringing them because it was depressing the survivors too much.
🔗 Read more: Why Doing Leg Lifts on a Pull Up Bar is Harder Than You Think
The Quack Doctors and the Smoking Craze
People were desperate. When you’re watching your neighbor develop "buboes"—those horrific, painful swellings in the groin and armpits—you’ll try anything. The College of Physicians was basically useless. Most of the real doctors fled the city as soon as things got hairy. Who could blame them?
Since science hadn't figured out germs yet, the prevailing theory was "miasma." Bad air. If it smelled bad, it was deadly. This led to some of the weirdest medical advice in history.
- Tobacco: Schoolboys at Eton were actually whipped if they refused to smoke. The idea was that the smoke would "clear" the plague air.
- Vinegar: People would dip their money in jars of vinegar at shops to "disinfect" it.
- Dried Toads: Some "doctors" suggested pressing a dried toad against the buboes to "draw out the poison."
- Pestilence Water: A cocktail of herbs, wine, and sometimes chemicals that usually just made the patient vomit.
The famous "Plague Doctor" mask with the bird beak? That was actually more common in mainland Europe, but the concept was the same: fill the beak with sweet-smelling herbs like lavender or camphor to block out the miasma. It didn't work. The fleas didn't care about lavender.
The Social Collapse and the Red Crosses
The government's response was, honestly, pretty brutal. If one person in your house got sick, the whole family was locked inside. For forty days. A watchman stood outside to make sure you didn't leave. This was basically a death sentence for everyone in the house. If you weren't sick when they locked the door, you probably would be within a week because you were trapped with a plague victim and their fleas.
💡 You might also like: Why That Reddit Blackhead on Nose That Won’t Pop Might Not Actually Be a Blackhead
This "shutting up of houses" is one of the most debated parts of the 1665 plague in London. Modern historians often argue it actually made the death toll higher. People tried to escape through the roofs or bribe the watchmen. If you had money, you left. King Charles II and his court hauled it to Oxford. The poor? They stayed and died.
The Myth of the Great Fire "Curing" the Plague
You've probably heard that the Great Fire of 1666 burned down the plague. It’s a clean story. It makes sense, right? Fire kills germs. But it’s mostly a myth.
While the fire did destroy the filthy, rat-infested slums in the city center, the plague was already tapering off by late 1665. Cold weather is what usually stops a plague outbreak because the fleas go dormant. Furthermore, most of the plague deaths happened in the "liberties"—the areas just outside the city walls—which the fire didn't even reach. The plague ended because it ran out of easy victims and the climate changed, not because the city burned down.
What it Feels Like to Trace the Dead Today
If you walk through London today, you are walking over the Great Plague. Because the churchyards filled up so fast, they had to dig "plague pits." These were massive, nameless trenches where bodies were piled high.
📖 Related: Egg Supplement Facts: Why Powdered Yolks Are Actually Taking Over
Aldgate, Tothill Fields, and even parts of what is now the London Underground are built near or over these sites. During the construction of the Crossrail project a few years ago, workers uncovered dozens of skeletons from the 1665 era at Charterhouse Square. DNA testing on the teeth of those skeletons confirmed it: Yersinia pestis. The evidence doesn't lie.
Modern Lessons from 1665
Looking back, the 1665 plague in London tells us a lot about how humans react to invisible threats. The scapegoating (they killed thousands of cats and dogs thinking they spread it, which actually made it worse because the rat population exploded), the flight of the wealthy, and the struggle between public health and personal liberty—it all feels eerily familiar.
To understand the plague is to understand the resilience of London. The city didn't just survive; it rebuilt. Within two years, the theaters were open again, and the shops were full.
How to explore this history yourself:
- Visit the Museum of London: They have an incredible collection of artifacts, though you should check their current location/reopening status as they move to Smithfield.
- Read the "Journal of the Plague Year": Daniel Defoe wrote this in 1722. While it's technically historical fiction (he was only a toddler in 1665), it's based on his uncle's journals and is incredibly accurate to the atmosphere of the time.
- Walk the City "Liberties": Spend time in areas like Shoreditch or Southwark. These were the epicenters where the poorest Londoners bore the brunt of the disease.
- Check the Parish Records: Many London churches still hold the 1665 registers. Seeing a page where every single entry is "P" for Plague is a sobering experience.
The Great Plague wasn't just a medical event. It was a moment where the old world and the new world collided. It was the last time the bubonic plague would ever hold London by the throat, ending a cycle of outbreaks that had lasted for centuries.
Actionable Insight: If you're researching the 1665 plague in London for academic or genealogical purposes, prioritize the digitized "Bills of Mortality" available through the Wellcome Collection or the National Archives. These primary sources provide the most accurate week-by-week breakdown of how the infection moved through specific London neighborhoods, far surpassing the generalized accounts found in most textbooks.