They pulled their theory out of the fact that "Dracula" was literally an honorifc name given to Vlad during his lifetime.
Stoker's Dracula and the "real" Dracula had only a few things in common: their name, being from Eastern Europe, being part of the nobility, having a castle. But they did have those things in common.
It was only later that someone speculated that Vlad could have been an inspiration, probably pulling this theory out of their ass.
Stoker's Dracula and the "real" Dracula had only a few things in common: their name, being from Eastern Europe, being part of the nobility, having a castle. But they did have those things in common.