Clive Leatherdale, in his book "Dracula: the romance and the legend-, sustains that the mythical figure of the Vampire is based on two popular beliefs as old as manhood: .
a) Faith in a Life after Death.
b) Faith in the magical "power- of blood.
About point a), it must be specified that this Life after Death should have place in an another world like Valhalla, Ade, Paradise and so on. The death is the limit between the real and the after-death world. This passage is very considered by every culture, and celebrated with special and peculiar ceremonies. A spirit or a dead corpse walking another time in the world of living beings means that the ceremony was not complete, not well-performed or, worse at all, it was stained by some kind of fault; now the spirit wants revenge! Also vampires fall in this category, dead in body but living in spirit, suspended forever on the thin borderline between Life and Death. .
Regard to the second point, it is easy to see that in many pre-industrial cultures blood is not only a symbol of vigour, life and health, but it is considered also the container of these mystical forces. Drinking the blood of a strong animal or enemy, or eating his flesh, was a way of absorbing his strength and prowess.
Therefore is hardly surprising that nearly all cultures, from Japanese to Greek, have legends and folk-tales with blood-sucking, undead monster, often capable of change themselves in to an animal or become invisible. The European versions of this myth are centred on the Balkan area; there are three historical periods that contributed in a crucial manner to form the present image of Vampires, the X, XV and XVIII centuries.
In X century, the Balkan Peninsula suffered the first raids by the Vikings stationed at Kiev. This expeditions, often performed at night by men covered with animal furs and filled with bloodlust (Berserks and Ulfheonars, wolf-man, so called after their habit of wearing a wolfhead as headgear), left a permanent trace in the folk-tales.