What is the historical accuracy surrounding the myth or legend of "Dracula"?
I assume you are referring to the widely accepted source for the Dracula myth. In the 15th century there was a Transylvanian leader called Vlad the Impaler. Some believed that Vlad was a tyrant and others that he was a dedicated leader. Either way, he made quite a name for himself and incited the wrath of many. Because of a special award he received, he gained the nickname Dracula, and during a time when he was trying to regain power that had been taken from him, pamphlets against him went into circulation. The pamphlets were titled: The Frightening and Truly Extraordinary Story of a Wicked Blood-drinking Tyrant Called Prince Dracula. This seems to be the main source for the legend.
There is a good, complete site below for all the history on this historical figure.