Bernstein Castle is a historical building in Bernstein im Burgenland, Austria, first mentioned in the 13th century. In 860 the whole region was part of the archbishopric of Salzburg. Erimbert, a liege of the archbishopric, handed over the Pinka to one Jacobus. The village name Rettenbach was not mentioned yet, but the old Slavic name of the nearby hamlet Grodnau (meaning "the village belonging to the castle") is a sign of the existence of a nearby castle, identifiable with castle Bernstein.
Since 1199 the castle was part of Hungary. It is not exactly known when the castle was handed over to Frederick II, Duke of Austria, and how long it was his property; but in 1236 Béla IV of Hungary conquered the castle. Some years later (in 1260) he gave it to count Henry II of Güssing.