The traits of modern-day vampires are pretty well established. They have fangs, drink human blood, and can’t see themselves in mirrors. They can be warded off with garlic, or killed with a stake through the heart. Some, like Dracula, are aristocrats who live in castles.

But vampires didn’t start out so clearly defined. Scholars suspect that the modern conception of these Halloween monsters evolved from various traditional beliefs that were held throughout Europe. These beliefs centered around the fear that the dead, once buried, could still harm the living.

Often, these legends arose from a misunderstanding of how bodies decompose. As a corpse’s skin shrinks, its teeth and fingernails can appear to have grown longer. And as internal organs break down, a dark “purge fluid” can leak out of the nose and mouth. People unfamiliar with this process would interpret this fluid to be blood and suspect that the corpse had been drinking it from the living. (Read “Archaeologists Suspect Vampire Burial; An Undead Primer.”)

Bloody corpses weren’t the only cause for suspicion. Before people understood how certain diseases spread, they sometimes imagined vampires were behind the unseen forces slowly ravaging their communities. “The one constant in the evolution of vampire legend has been its close association with disease,” writes Mark Collins Jenkins in his book Vampire Forensics. Trying to kill vampires, or prevent them from feeding, was a way for people to feel as though they had some control over disease.

WATCH: Go inside an annual vampire ball.

Vampires of Europe

Because of this, vampire scares tended to coincide with outbreaks of the plague. In 2006, archaeologists unearthed a 16th-century skull in Venice, Italy, that had been buried among plague victims with a brick in its mouth. The brick was likely a burial tactic to prevent strega—Italian vampires or witches—from leaving the grave to eat people. (Read “‘Vampire of Venice’ Unmasked: Plague Victim & Witch?”)

Not all vampires were thought to physically leave their grave. In northern Germany, the Nachzehrer, or “after-devourers,” stayed in the ground, chewing on their burial shrouds. Again, this belief likely has to do with purge fluid, which could cause the shroud to sag or tear, creating the illusion that a corpse had been chewing it.

These stationary masticators were still thought to cause trouble aboveground, and were also believed to be most active during outbreaks of the plague. In the 1679 tract “On the Chewing Dead,” a Protestant theologian accused the Nachzehrer of harming their surviving family members through occult processes. He wrote that people could stop them by exhuming the body and stuffing its mouth with soil, and maybe a stone and a coin for good measure. Without the ability to chew, the tract claimed, the corpse would die of starvation.

Tales of vampires continued to flourish in southern and eastern European nations in the 17th and 18th centuries, to the chagrin of some leaders. By the mid-18th century, Pope Benedict XIV declared that vampires were “fallacious fictions of human fantasy,” and the Hapsburg ruler Maria Theresa condemned vampire beliefs as “superstition and fraud.”

Still, anti-vampire efforts continued. And, perhaps most surprisingly of all, one of the last big vampire scares occurred in 19th century New England, two centuries after the infamous Salem witch trials.

From the Old World to the New

In 1892, 19-year-old Mercy Brown of Exeter, Rhode Island, died of tuberculosis, then known as consumption. Her mother and sister were already dead, and her brother Edwin was sick. Concerned neighbors worried that one of the recently deceased Brown women might be harming Edwin from the grave.

When they opened Mercy Brown’s grave, they found blood in her mouth and her heart and took this to be a sign of vampirism (though they didn’t call it that). The neighbors burned Mercy’s heart and mixed the ashes into a potion for Edwin to drink—a common anti-vampire tactic. The potion was meant to heal him; instead, he died a few months later.

This wasn’t an isolated incident. Folklorist and Food for the Dead author Michael Bell estimates that there are 60 known examples of anti-vampire rituals in 18th- and 19th-century New England, and several others elsewhere in the country. These rituals were most common in eastern Connecticut and western Rhode Island, says Brian Carroll, a history professor at Central Washington University who is writing a book on the subject.

Carroll believes these anti-vampire rituals were “introduced as a medical procedure at the time of the American Revolution” by German doctors who worked for the Hessian forces. Because of this, he thinks the New England vampires were based on the German Nachzehrer. Unlike blood-sucking Romanian vampires, New England’s vampires stayed in their grave, harming the living through “sympathetic magic” from afar, he argues.

Bell, however, believes anti-vampire practices in New England came from many places and that the suspected New England vampires were actually more akin to Romanian vampires than the Nachzehrer. Like Romanians, New Englanders “were looking for liquid blood in the vital organs, not evidence of shroud chewing,” he says. The anti-vampire remedy of “cutting the heart out, burning it to ashes, and giving the ashes to the sick person or sick people” was also practiced in Romania.

Whatever the source of these beliefs in New England, they were driven by the same social concerns as those before them: a fear of disease and a desire to contain it.

View Images This 16th-century skull was buried in Venice, Italy, with a brick in its mouth. The brick was likely meant to prevent the person from leaving the grave to eat people. Photograph courtesy National Geographic Television

Post-Vampire

During the vampire panic in New England, vampires were finding a new role in European books like The Vampyre (1819), Carmilla (1871-72), and Dracula (1897), as well as in vampire-themed plays. Though drawn from folk legends and past vampire scares, these aristocratic, sexual vampires were more like the vampires we know today.

Vampire panics died down in the 20th century as these fictional monsters replaced folk beliefs (and as medical knowledge improved); however, there was a strange resurgence in the late 1960s, when Seán Manchester, the president of the British Occult Society, said that a vampire was causing people to see strange things in London’s Highgate Cemetery.

Newspapers had already covered reports of a tall figure with burning eyes and other spectral sights floating in the cemetery, and journalists quickly picked up Manchester’s theory that these sightings were the work of an eastern European vampire. Newspapers even embellished his claims a bit, calling the figure a “king vampire,” or writing that the vampire had practiced black magic in Romania before traveling to London in his coffin.

In 1970, Manchester told a TV news team that he planned to exercise the vampire on Friday the 13th. That night, hundreds of young people turned up at Highgate Cemetery to see him perform an exorcism (which he ended up not doing).

The Highgate panic wasn’t a case of vampires being scapegoated for disease but rather a media sensation and an instance of “legend tripping” (young people going to a supposedly haunted place to test their bravery).

In the history of vampire legends, the Highgate incident is a modern phenomenon. It has less to do with the desire to control a community’s health and a lot more in common with modern scares, like the creepy clown sightings that went viral this year—even if people don’t believe it, they’re still drawn to the hype.