Because Vampires are mythical creatures, there is no specific description that has stayed the test of time. The only attribute is of an undead creature who survives by consuming the blood of other animals or people. Many cultures around the world have similar mythologies and it may be based on people sometimes suspecting vampirism when a cadaver did not look as they thought a normal corpse should when disinterred. Often corpses become bloated and the skin darkened, with blood coming from the mouth and nose as though they had recently consumed blood. Piercing the skin with a sword or wooden stake would release the gasses and ensure the corpse could not reanimate.By the 17th Century the folkloric tales of vampyres became widespread in Eastern Europe and these tales formed the basis of the vampire legend that later entered Germany and England, where they were subsequently embellished and popularized. During the mid 18th century, panic began with an outbreak of alleged vampire attacks in East Prussia and this spread across the Hapsburg empire. Two incidents were well-documented in Serbia which led to locals digging up bodies and in some cases, staking them.
Several novels and stories appeared across Europe in the 19th century based on similar tale:. John Polidori's "The Vampyre" (1819) and some penny dreadful serial publications such as Varney the Vampire (1847) for instance but it was Bram Stoker's Dracula (1897) which depicted vampirism as a disease of contagious demonic possession, with its undertones of sex, blood and death. His depiction became the foundation of the modern vampire legends. Although Stoker used the name of Vlad Dracul in his stories - a 15th century Romanian warlord with a reputation for horrific barbarity - this is likely just because he liked the name.
Vampire bats are native to South America and therefore were largely unknown in Europe until the 19th century. They were named for the legend and not the other way around and the connection to Bats and vampires is a largely modern invention. Come along to the Banshee Labyrinth tonight to hear Tracey Jolliffe talk about The Secret History of Bats - 7:20.