Leopold Grabner zu Rosenburg, Pottenbrunn and Siebenbrunn (born probably 1528 at Rosenburg castle; died 1583 ibid), also Leopold Grabner (zu Rosenburg), during his lifetime Leopold Grabner zu Rosenberg, was a nobleman of the Archduchy of Austria below the Enns. During the Reformation, Grabner was one of the leading Protestants in the country, a deputy of the estates and councillor. Under him, Rosenburg castle became a center of Austrian Reformation history.[1]