For the people of medieval Europe, death was a constant companion. Disease, war, or famine could, and frequently did, put kings and peasants alike into an early grave. In fact, the average life expectancy for a child born in the UK during the 13th century was a mere 31 years. The constant presence of death was reflected in religion, art, and the popular imagination. And in an era before modern science, medieval peasants often struggled to understand why an otherwise healthy person might suddenly grow sick and die, almost as if the life was being drained out of them.
Even harder to understand was when deaths tended to occur within a single family. After all, the death of a single person can be a random tragedy, but the deaths of an entire family in quick succession seemed almost as if there was an unseen force at work. As they often did, medieval people attributed these kinds of sudden deaths to the supernatural. The explanation they often arrived at was that the bodies of those who had recently died rose from the grave and returned to their homes, draining the life of the family members they had left behind.
This dark creature that fed on the life of the living was known by many different names. In Slavic mythology, they were the “vampir.” To the Chinese, they were the “jiangshi.” And in English folklore, the creature was known as a “revenant,” or “one who returns.” There were a number of things that could turn a fresh corpse into a revenant. Anyone who was especially violent or evil in life could become a revenant, as could anyone who committed suicide. And anyone who was excommunicated by the Christian Church was likely to rise again.
Once out of the grave, the revenant would prowl through the night visiting the homes of relatives or people they knew in life. According to some stories, the revenant feeds on the blood of the living. In others, they simply spread disease through the house or drain the life from the occupants with dark magic. And according to King James I in a treatise he wrote on the various varieties of demons, revenants were possessed by evil spirits who would use the dead body to have sexual relations with women in order to birth unholy demon spawn. Unlike vampires, there was little one could do to repel revenants, so the best option was to stop them from leaving the grave.
You could prevent revenants from rising by identifying people who were likely to become revenants and dismembering their bodies before burial. The most important things to remove were the head and the heart. Once cut from the body, both had to be burned. But if you were too late to stop the body from rising again, then it had to be dug up and totally destroyed by dismemberment and fire, or, at the very least, blessed by a priest and re-buried. And while the whole idea seems strange to us, there was actually a reason that the belief in revenants was so common.