GRAND-DUKE (Fr. grand-due, Ital. granduca, Ger. Grosshcrzog) , a title borne by princes ranking between king and duke. The dignity was first bestowed in 1567 by Pope Pius V. on Duke Cosimo I. of Florence, his son Francis obtaining the emperor's confirmation in 1576; and the predicate "Royal Highness" was added in 1699. In 1806 Napoleon created his brother-in-law Joachim Murat, grand-duke of Berg, and in the same year the title was assumed by the landgrave of Hesse-Darmstadt, the elector of Baden, and the new ruler of the secularized bishopric of Wiirzburg (formerly Ferdinand III., grand-duke of Tuscany) on joining the Confederation of the Rhine. At the present time, according to the decision of the Congress of Vienna, the title is borne by the sovereigns of Luxemburg, Saxe-Weimar ( grandduke of Saxony), Mecklenburg-Schwerin, Mecklenburg-Strelitz, and Oldenburg (since 1829), as well as by those of Hesse- Darmstadt and Baden. The emperor of Austria includes among his titles those of grand-duke of Cracow and Tuscany, and the king of Prussia those of grand-duke of the Lower Rhine and Posen. The title is also retained by the dispossessed Habsburg-Lorraine dynasty of Tuscany.
Grand-duke is also the conventional English equivalent of the Russian velikiy knyaz, more properly " grand-prince " (Ger. Grossfurst), at one time the title of the rulers of Russia, who, as the eldest born of the house of Rurik, exercised overlordship over the udyelniye knyazi or local princes. On the partition of the inheritance of Rurik, the eldest of each branch assumed the title of grand-prince. Under the domination of the Golden Horde the right to bestow the title velikiy knyaz was reserved by the Tatar Khan, who gave it to the prince of Moskow. In Lithuania this title also symbolized a similar overlordship, and it passed to the kings of Poland on the union of Lithuania with the Polish republic. The style of the emperor of Russia now includes the titles of grand-duke (oellkiy knyaz) of Smolensk, Lithuania, Volhynia, Podolia and Finland. Until 1886 this title grand-duke or grand-duchess, with the style " Imperial Highness," was borne by all descendants of the imperial house. It is now confined to the sons and daughters, brothers and sisters, and male grandchildren of the emperor. The other members of the imperial house bear the title of prince (knyaz) and princess (knyaginya, if married, knyazhna, if unmarried) with the style of " Highness." The emperor of Austria, as king of Hungary, also bears this title as " grand-duke " of Transylvania, which was erected into a " grand-princedom " (Grossftirstentum) in 1765 by Maria Theresa.