A Vampire, by definition, is an entity that feeds on the life essence of other creatures. Vampires are typically described as "undead" — reanimated corpses possessed by evil spirits.
The traditional vampire
feeds on the blood of the living to prevent its body from decomposing. The image of the refined, gaunt, pale-skinned vampire is an early 19th century literary invention, beginning roughly with the publication of The Vampyre — a short story by John Polidori — in 1819.
The original, folkloric vampire of Eastern Europe — where the legend began — was described as bloated with a dark or ruddy complexion from feeding on blood.
Many attribute belief in vampires to a combination of Slavic spiritualism and early ignorance of the body's decomposition cycle after death.
In pre-industrial Slavic societies, it was believed that a person's spirit lingered for 40 days after death. Suicide victims, suspected witches, evil beings and even un-baptized children were thought to have "unclean" spirits.
A vampire, according to this belief, was the manifestation of an unclean spirit possessing a decomposing body. When the body of a suspected vampire was disinterred, it would sometimes look like it hadn't decomposed at all; like its hair, teeth and fingernails had been growing; and as if it had been gorging on blood due to its ruddy complexion, bloated body and blood seeping from the nose and mouth.
We know now that a body's decomposition rate depends on factors like temperature and soil composition; that dead flesh loses fluids, causing it to pull back and expose the roots of hair, teeth and nails; and that gases from decomposition accumulate in the torso, making the body look bloated and forcing blood to ooze from the nose and mouth.
Common beliefs about vampires include that they are most active at night, but not necessarily vulnerable to sunlight (which was mainly a literary invention).
Garlic, crucifixes and holy water were common devices for warding off vampires. It was also commonly believed that driving a wooden stake into the body would release the evil spirit, with decapitation also being a way to hasten the evil soul's departure.
Strigoi
Strigoi were vampirelike creatures originating from Romania that were believed to be the spirits of deceased people who had led troubled lives. According to Romanian folklore, most strigoi had crimson hair, indigo eyes and two hearts, but it was difficult to recognize one since they usually took the form of other entities.
This spirit survived by drawing blood from people and often transformed into animals or poltergeists in order to create chaos in the real world. For example, Romanians blamed strigoi for conditions like disease and famine.
According to legend, there were many potential scenarios that could cause someone to become a strigoi after death, but this fate was usually the result of leading a troubled or unfinished life.
For example, a person born out of wedlock supposedly was destined to return as a strigoi, along with those who died before being baptized or people who died of an unnatural death. Children with certain birth defects were at one time said to be living strigoi, known as strigoi viu.
Historically, there were a variety of ways people ensured a loved one could not return as a strigoi. For example, some believed that burying a bottle of whiskey with the deceased would keep him or her from returning, while others destroyed the body prior to burial.
If a family believed the deceased had returned as a strigoi, they might have exhumed the body and destroyed it or driven spikes through its heart to ward off the strigoi for good. If after seven years, a strigoi survived, it could live as an ordinary person and even have a family again.