ARCHDUKE (Lat. archidux, Ger. Erzherzog,) a title peculiar now to the Austrian royal family. According to Selden it denotes "an excellency or pre-eminence only, not a superiority or power over other dukes, as in archbishop it doth over other bishops." Yet in this latter sense it would seem to have been assumed by Bruno of Saxony, archbishop of Cologne, and duke of Lorraine (953-965), when he divided his duchy into the dukedoms of Upper and Lower Lorraine. The designation was, however, exceedingly rare during the middle ages. The title of archduke of Lorraine ceased with the circumstances which had produced it. The later dynasties of Brabant and Lorraine, when these fiefs became hereditary, bore only the title of duke. The house of Habsburg, therefore, did not acquire this title with the inheritance of the dukes of Lorraine. Nor does it occur in any of the charters granted to the dukes of Austria by the emperors; though in that creating the first duke of Austria the archiduces palatii, i.e. the principal dukes of the court, are mentioned. The "Archidux Austriae, seu Austriae inferioris" is spoken of by Abbot Rudolph (d. 1138) in his chronicles of the abbey of St Trond (Gesta Abbatum Trudonensium) but this is no more than a rhetorical flourish, and the title of "archduke palatine" (Pfalz-Erzherzog) was, in fact, assumed first by Duke Rudolph IV. (d. 1365), and was one of the rights and privileges included in his famous forgery of the year 1358, the privilegium maius, which purported to have been bestowed by the emperor Frederick I. on the dukes of Austria in extension of the genuine privilegium minus of 1156, granted to the margrave Henry II. Rudolph IV. used the title on his seals and charters till he was compelled to desist by the emperor Charles IV. The title was also assumed for a time, probably on the strength of the privilegium maius, by Duke Ernest of Styria (d. 1424); but it did not legally belong to the house of Habsburg until 1453, when Duke Ernest's son, the emperor Frederick III. (Frederick V., duke of Styria and Carinthia, 1424-1493, of Austria, 1463-1493), confirmed the privilegium maius and conferred the title of archduke of Austria on his son Maximilian and his heirs. The title archduke (or archduchess) is now borne by all members of the Austrian imperial house.
See John Selden, Titles of Honor (1672); Antonius Matthaeus, De nobilititate, de principibus, deducibus, etc., libriquatuor (Amsterdam and Leiden, 1696, lib. i. cap. 6); Pfeffel, Abrégé chronologique de l'hist, el du droit public d'Allemagne (Paris, 1766); Brinckmeier, Glossarium diplomaticum, etc. (1850-1863, 2 vols.); J.F. Joachim, "Abhandlung von dem Titel 'Erzherzog,' welchen das Haus Oesterreich fuhrt." in Prufende Gesellschaft zu Halle, 7; F. Wachter, art. "Erzherzog," in Allgem. Encykl. der Wissenschiften u. Kunste (1842, pub. by Ersch and Gruber); A. Huber, Ueber die Entstehungszeit der oesterreichischen Freiheitsbriefe (Vienna, 1860); W. Erben, Das Privilegium Friedrichs I. für das Herzogtum Osterreich (Vienna, 1902).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)