Definition of "heyduke"

[I]n the village of Medreyga in Hungary, certain dead Bodies (call'd there Vampyres) had kill'd several Persons by sucking out all their Blood: That Arnold Paul, an Heyduke, having kill'd four Persons after he was dead, his Body was taken up 40 Days after[.]

1732 May 20, The London Journal, page 76, column 1