Throughout history the legend of the vampire has been used to "explain" other natural phenomena that primitive people who lacked scientific knowledge could not otherwise explain. Possibly the most astonishing belief which people associated vampires with was the Black Death during the Middle Ages in Europe.
The Black Death, as we now know, was actually Bubonic plague spread by fleas and rats. The plague (which came from the East, not unlike the vampire) may have killed as much as a third of the population of Europe in the 1300s. Some people of the day, however, associated the multitude of deaths with vampires. Somehow they believed that the deaths were the workings of these monsters; perhaps the vampires spread plague, they may have thought. In some cases people believed a deceased relative returned as a vampire and killed a victim (who actually died of the plague). Alternately, it was believed a dead enemy could return and kill someone turning the victim into a vampire as well. Many graves were dug up and the bodies of suspected vampires mutilated to "kill" the vampire.
Idiotic methods were used to "locate" the graves of vampires. For example, a virgin was placed naked on a horse, and the horse was paraded through a graveyard. If the horse (which was apparently more intelligent than the people) decided not to walk over a certain burial site, this was assumed to be the grave of a vampire. The body was immediately exhumed and mutilated to "kill" the vampire and, yes, thereby stop the plague which was devastating the region.
Some of the most foolish vampire beliefs involved the methods used for killing vampires or stopping the spread of vampirism. It is important to remember, however, that while these beliefs seem absurd today, in an age when ignorance ruled unchecked, desperate people became susceptible to the power of superstitions.
Corpses were sometimes buried face-down. If the corpse became a vampire it would actually dig deeper into the ground in an attempt to escape the grave, if it was facing the wrong direction -- or so it was thought. Wooden stakes were sometimes planted in the ground above the grave, so if the body rose it would stab itself on the stake -- hopefully through the heart.
Corpses were sometimes wrapped in a carpet or cloth to make it more difficult for them to rise from the dead. Alternately, the legs or arms were tied up with rope.
Large rocks were often placed over the grave to prevent the corpse's return. (Could this possibly be the origin of the modern tombstone?) And it is significant to note that some people consider the vampire to be a type of ghost which lives after death, transcending the grave. What better way to keep the ghost in the grave than seal it in stone?
The natural process of bodily decomposition after death sometimes convinced people that corpses were actually transforming into vampires: the hair and nails continued to grow, indicating continued life; the corpse bloated from naturally occurring gasses in the body, meaning it fed on the living; blood sometimes appeared near the mouth as a natural result of bodily decay, indicating the drinking of blood; the generally grotesque appearance of the corpse complete with pale skin, indicating a vampiric need for blood.
Ignorant people followed superstitions to thwart assault from vampires, too. Two of the most commonly known substances used to scare away vampires were the herbs "wolfsbane" and, of course, garlic. It is theorized that people during the Middle Ages believed that the horrible smell of the dead was related to the cause of death, especially during the Black Death, and that the deaths were somehow related to vampires. It is not unlikely that herbs would be used to counteract the smell of death, considering the potent aroma of garlic. Also, throughout the ages garlic had been used as a medicinal herb even by the ancient Romans. Ironically enough, modern science also believes garlic can help people become healthier, in some cases.
People developed curious beliefs relating to vampires. Some believed if a black cat or dog jumped over a corpse, the deceased could turn into a vampire. In Bukovinian lore a stake of ash wood should be driven through the chest of those who died by suicide; suicide being a presumed cause for vampirism. In several cultures, including old England, people who committed suicide were buried at a crossroads (a sign of the cross made by roads) to prevent the corpse from becoming a vampire.
Various people had their various methods for destroying vampires as well. In some Slavic nations a spike made of ash wood, if driven through the chest, was believed to kill a vampire -- this is everyone's favorite method, a stake through the heart. In different lands, however, the wood used sometimes needed to be from a certain tree. For example, oak wood did the job in Silesia, while hawthorn wood was required in Serbia.
Additionally, the heads of corpses suspected of being vampires were sometimes chopped off. Sometimes corpses were thrown into pools of water or burned.
These beliefs were based on the general ignorance of the population, but the greater tragedy of the vampire legend was that the actual ascendance of the belief of the vampire myth may have been helped through the deeds (and misdeeds) of organized religion.
The Church in Europe during the Middle Ages came to recognize the existence of vampires and changed it from a pagan folk myth into a creature of the Devil. The vampire, though clearly a thing of evil and a pagan myth, had its believability reinforced by preexisting Christian doctrines such as life after death, the resurrection of the body, and "transubstantiation." This was a concept based on the Last Supper and the dogma of Pope Innocent the III in 1215 A.D., that the "bread and wine" and its equivalent during Christian Communion literally transubstantiated into the actual body and blood of Christ. People who adhered to this belief, and who consumed the blood of Christ, would have little difficulty in believing the corrupted corollary to this -- the drinking of blood by evil demons, namely, vampires.
The Church during the Middle Ages gave credence to the belief in vampires, concluded that it alone had the power to stop vampirism, and then reinforced this position two centuries later in 1489 with its landmark book, Malleus Maleficarum. This work was actually designed to deal with the persecution of witches, but it could be applied to evil vampires as well. Unfortunately many innocent people fell victim to this document, and were tortured and executed for no good reason whatsoever. This book, known as The Hammer Against Witches in English, was used to help identify and persecute people who were supposedly in league with the Devil.
Two centuries after this, evidence that the Church still clung to a belief in vampires was found in the writing of the noted theologian Leo Allatius. As a Church scholar he studied the vrykolakas, the Greeks' concept of the vampire. In his 1645 work called On the Current Opinions of Certain Greeks, he concluded that vampires were often the result of excommunication. Proof of their vampirism is that the body does not decay, indicating that it cannot leave this earthly plane. A swollen body was also evidence of possible vampirism. As some bodies might not decay rapidly due to the type of chemicals in the soil or the cold air temperature, and since bodily swelling was the result of naturally produced gasses in a corpse, many a dead man was wrongly presumed to be a vampire. Oddly enough, incorruptibility --the failure of the dead body to decay -- was also a sign of holiness, even evidence of saintliness. The difference was that a vampire did not totally decay but did become grotesque in form with discoloration and bloating, while a holy body remained almost perfectly intact as if still alive. Also, vampires smelled bad during the lack of decay, whereas sanctified bodies did not. (Remember, you needed garlic to overcome the smell of the vampire's corrupting but non-decomposed, undead body.)
Furthermore, it was a common belief of early Greek Christians that a priest or bishop upon excommunicating an evil-doer could also prevent the sinner's body from decomposing, hence the soul would not be free to go to heaven and was left to dwell on earth until it received a pardon for its sins. In the western Church this belief was apparently also held. There was the case of the Archbishop of Bremen in the 10th century, St. Libentius. He was said to have excommunicated some pirates; the body of one of them was allegedly discovered many years later still undecomposed. It apparently required a pardon of its sins by a bishop before its body would dissolve to ashes -- so it was believed. The clergy thus had the power to make or break possible vampires through excommunication and absolution.
Leo Allatius may have been one of the first scholars to declare officially that vampires were under the power of the Devil and that they prowled at night.
Proof of the Church's power over vampires (and hence the power of the crucifix or holy cross to scare off vampires -- although more modern vampires appear to be less susceptible to this) dates all the way back, at least, to Medieval England. A writer named William of Newburgh discussed the case of a man who died in the 12th century A.D. Supposedly he rose from the dead to torment his wife. After causing much consternation with the local villagers and clergy, the bishop of the region pardoned the corpse in writing for all his past sins. The grave was opened and the actual written pardon was placed over the body of the "vampire." The people were surprised -- or maybe not -- to see the body was still in good condition without signs of decay, sure proof of vampirism. But fortunately for everyone, once the pardon was placed in the grave, the vampire visited no more. Note that this method of dispelling the vampire with an official Church document was remarkably more civil and legalistic than the ordinary way peasants would dispense with a vampire found in the grave -- by burning the corpse, ripping out its heart, chopping off its head, or giving it the old wooden stake through the heart.
In the early 1700s the Sorbonne university in Paris formally opposed the all too common practice in popular culture of mutilating corpses to prevent the dead from becoming vampires. The Sorbonne (which the renowned writer Voltaire had once been shocked to discover actually debated the legitimacy of the mythological vampire) finally took the apparently radical position at that time that the mutilation of corpses suspected of vampirism was a practice based on irrational superstitions.
The belief in vampires, however, did not go without intelligent criticism. Dom Augustine Calmet, a French Benedictine monk, actually wrote a book in 1746 which dared to question the existence of vampires, called A Treatise on Apparitions, Spirits and Vampires a.k.a. The Phantom World. Calmet challenged the rampant vampire superstitions of the day and required proof before acceptance of a belief. He especially doubted that vampires could perform superhuman tasks, such as rising from the dead. He also analyzed and critiqued the supposed vampire epidemics throughout Europe, questioning their basis in reality.
Eventually the centuries of ignorance and superstition gave way to the Age of Reason and Enlightenment and the rise of the scientific method. Eventually medical science was able to prove that plagues, such as the Black Death, were not spread by evil, metaphysical vampires but had a very physical, although microscopic, biological basis.