Vampires are Evil or Demonic
Vampires are no more evil than any other person. Whether a vampire chooses to do good deeds or evil ones is an individual choice just like anyone else. Vampirism is not a curse, a spell or a punishment.
Those Bitten By Vampire Will Turn Into Vampire
Drinking A Vampire's Blood Turns People
This myth seems to go as far in history back as the vampire itself. This could be because of rabies. Rabies may be the oldest infectious disease known to man. Even ancient civilizations knew that rabies was transmitted through a bite so they probably assumed vampirism was transferred the same way. It was not until Bram Stoker's "Dracula" it was thought to be because the person was bitten by the vampire and then drank the blood of the vampire.
Vampirism is caused by a virus or retrovirus
There are many theories as to the cause of vampirism and the true cause of it has yet to be determined. This theory though has recently arose and it is generally agreed through out the vampire community to be false. This theory was mentioned in ''Ultraviolet'' a British TV series as well as in the book ''Children of the Night'' by Dan Simmons, 1992.
Further research into retro viruses can be found here:
Allergic To Garlic
New World Encyclopedia, Retrovirus!
The History of Virology
A Brief History of Microbiology
This myth seems to have come about because the people believed that the strong odor from the garlic would repel the vampires. Although some individual vampires may have an allergy to garlic or some other food allergy, this is not true for most vampires. In addition garlic is understood today to be of importance as a medicinal herb, often used to treat many blood related conditions or to improve overall health.
Allergic To Holy Water
Water has long been considered to be pure and cleansing. If a holy man also blessed this water then the people believed it would of course harm a vampire since vampires were thought to be unclean and evil.
Allergic To Silver
Although silver was usually associated with repelling or harming werewolves so myths also mention it as a tool against vampires. Silver was long considered to be a pure and even holy metal and would harm the foul and evil vampire.
Sunlight will kill a vampire
Although vampires are sensitive to the sun and bright lights, often to the extent that prolonged expose will make a vampire feel weak and quite ill, being in the sunlight will not kill a vampire. Partly this myth evolved because of the thought that vampires are evil and evil would be at home in the darkness rather than in the light of the sun. For quite a while people believed that the sun and it's warming light was either a gift from their god or controlled by their god therefore because they believed vampires to be evil, the hallowed sunlight would naturally be harmful to such a creature. Many people can and do become ill if exposed to too much sunlight but with vampires it occurs a bit sooner.
Repelled By Religious Symbols Or Crosses
The only way a cross or any religious symbol will repel a vampire is if that vampire is religious and wrongly believes that their condition is a result of a curse or punishment put upon them by their god. Many vampires are religious and followers of various religions such as Christianity, Judaism, Islam, Buddhism, Wicca, Paganism or Satanism although some are agnostic or atheist.
Unable To Cross A Line Of Salt
Salt is an effective preservative, since most bacteria can't survive in an extremely salty environment. Some ancient cultures believed that evil spirits caused sickness, noticed that salting the meat prevented rot and therefore sickness. Having no understanding of microbiology, they came to believe that salt possessed the power to repel evil. Gradually it became incorporated into various religious practices and superstitions. Salt was a symbol of incorruption, a covenant which could not be broken.
Unable To Cross A Thicket Of Wild Rose
It was said that placing a branch of wild rose across a vampires grave prevented it from leaving the grave to attack people.
Unable To Cross Running Water
Both the Greeks and the Chinese state in their myths that vampires can not cross running water such as a stream or salt water such as an ocean. The vampires could be carried across in a boat or over a bridge and could also cross it at high or low tide. The Greeks would bury a suspected vampire on an off shore island to prevent them from attacking people.
Capable Of Turning Into Mist Or Other Forms
Capable Of Flight
This myth probably came about through the attempts of people to explain how the vampire either rose from it's grave or entered their home. Adding to it was the lack of the people's ability to explain the appearance of the vampire.
Not all ancient myths referred to vampires as immortal. Some even specified the number of days after death that the vampire would roam the earth. Most myths assumed that the vampire was already dead and therefore was also immortal.
Long Sharp Fangs
People naturally associate predators with long fangs. All of the large predators have them so people of course assumed that vampires had them too.
Do Not Consume Food Or Drink
Some ancient myths actually stated the opposite. Declaring that vampires would begin their roaming because they missed the foods that they enjoyed. This often led to offerings being left at the grave of a suspected vampire so that it would be satisfied and not roam. Also many felt that since a vampire is no longer living it had no need to eat or drink.
Sleep In Coffins
Must Sleep In The Earth Or Dirt
These myths came from the experiences of the people who exhumed the graves of suspected vampires only to find them still occupied by the deceased. Without a proper understanding of what happens to bodies after burial and how the environment can alter the decay, many corpses were thought to be vampires. In addition since most ancient vampires of myth attacked those that they knew from their life, it was often believed that the vampire could not travel far from it's grave. Later the vampire needing to take as much as a pound of soil from their grave with them if they should travel a distance from their original burial site supposedly resolved this.
Must Be Invited To Enter A Residence
This myth first seemed to arise in Greece and Romania as a belief that at night, a vampire makes his way to what so ever house he chooses, and knocking upon the door he calls by name to one who dwells within. If that person answers he will die by the next day. But if he does not answer he is safe. In some beliefs the vampire may ask only twice, so the people would not respond to the call until after third time because then it must surely be a person and not a vampire. Later Bram Stoker embellished on this myth in Dracula, Chapter 18, Professor Van Helsing in Mina Harker's Journal "He may not enter anywhere at first, unless there be some member of the household to bid him to come; though afterwards he can come as he pleases."
Sparkle in sunlight
This myth was unheard of until created in 2003 by Stephenie Meyer in "Twilight". Although not all ancient vampire myths mention an aversion to sunlight none even hint at such an extreme side effect as sparkling in sunlight.
Do not need to sleep
This myth also was unheard of until created in 2003 by Stephenie Meyer in "Twilight". In fact some ancient myths had the vampire rising from their graves only to attack.