Schlaining Castle was first mentioned in 1271 as "castrum Zloynuk" and owned by the Counts of Güssing. In the 16th century it came into the hands of the Counts Batthyány. Today it belongs to the Federal State of Burgenland and is run as a museum, with seminar and conference rooms. Since 1983 it houses also  the "Austrian Study Center for Peace and Conflict Resolution (ASPR)".