Carol has the right of it as far as the legend goes (the noblewoman’s name was Elizabeth Bathory. She’d give Hannible Lector chills. Read her bio some day if you’ve got the time).
As far as the castle goes: I was in the area several years ago and was contemplating a trip to visit the castle. A little poking around (Fordor, probably) revealed that the castle that was “Castle Dracula” was never really where Vlad hung his banner. It just looks like a cool medieval castle. I never went.
If you want a brief historical blurb on the actual “Dracula” castles, try this link:
There are hundreds of others, probably with conflicting information, but that’ll get you started.