The character in Bram Stoker's Gothic novel Dracula, published 1897, was based on the real life chilling personality of Vlad the Impaler (1431-1476). Vlad's is a complex history of power and ugly revenge, and space does not permit a fair recounting; so if it interests you, you can check out the stories, real and fictional, here.
Yet the castle described in the classic book was based on this fortress in Bran, a few hours drive north of Bucharest, where Vlad never lived. Nonetheless, it is now nicknamed Dracula's Castle.
Have you read the book? A friend cajoled me to read it in the 80s and it's a heckuva compelling story. Having now seen Bran Castle, inside and outside, I am tempted to reread the novel.