We have all heard of Vampires. This is a dead person who wakes at night to turn into a bat, (if necessary) run out and suck someone’s blood, and lives as long as they can do this and no body puts a stake through their heart.
Much of what we know about Vampires comes from ‘Dracula’, a book by Bram Stoker, which describes a Count Dracula who lived in Romania.
<a href="https://commons.wikimedia.org/wiki/File:Vlad_Tepes_002.jpg" target="_blank" rel="noopener">Source</a>
Many claim this Count was based a a real person called Vlad Dracula, who was nicknamed Vlad Tepes (Vlad the Impaler). He was the ruler of Walachia and born in 1431 in Sighisoara.
He has a rather unpleasant biography.
As to Vampires, there was a genuine epidemic of belief in “vampirism” in Eastern Europe from the end of the 17th century into the 18th century. This belief moved to Germany, Italy, France, England and Spain.
<a href="https://en.wikipedia.org/wiki/Count_Dracula" target="_blank" rel="noopener">Source</a>
Persons would tell stories about the undead, which helped keep the interest in vampires alive. Bram Stoker’s novel in 1897 came after a long series of works based on these tales. He basically took the tales he had heard, and using bits and pieces, created his ‘Count Dracula’.
Readers were certain that the novel had been inspired by real facts.
<a href="http://dailygreatest.com/funfacts/12-of-historys-worst-female-serial-killers/" target="_blank" rel="noopener">Source</a>
There is a true story of a woman, Elizabeth Bathory, who used to kill young girls and drink and bath in their blood to keep herself young. She was arrested, convicted, and locked into a crypt, and survived for four years.
Scientifically, getting infusions of young blood does have a true regenerative capability, so there might be something to Vampirism.