Herzog (pronounced [ˈhɛʁtsoːk] ⓘ; feminine Herzogin [ˈhɛʁtsoːɡɪn] ⓘ; masculine plural Herzöge; feminine plural Herzoginnen) is a German hereditary title held by one who rules a territorial duchy, exercises feudal authority over an estate called a duchy, or possesses a right by law or tradition to be referred to by the ducal title.
Several dynasties, such as the Habsburgs of Austria, Hohenzollerns of Prussia, Welfs of Hanover, Wettins of Saxony, Wittelsbachs of Bavaria, and the House of Württemberg, held the Herzogswürde ('dukedom') before becoming kings.
Although a Herzog ranked below a Kurfürst ('prince-elector') within the Empire, he also belonged by hereditary right to the Fürstenbank ('Chamber of Princes,' lit.
'princely seat') within the Reichstag, exercised Landeshoheit within his imperial state, and enjoyed Reichsunmittelbarkeit within the Empire.
Occasionally, the Emperor conferred the title of Herzog on a nobleman who was not necessarily a Prince of the Holy Roman Empire and did not rule a duchy.