were divided into Nassau-Weilburg and Nassau-Wiesbaden-Idstein. Nassau-Weilburg (1344–1816) Count Walram II began the Countship of Nassau in Weilburg (Nassau-Weilburg), which existed to 1816. The Walram line also received the lordship of Merenberg in 1328 and Saarbrücken (by marriage) in 1353. The sovereigns of this house afterwards ruled the Duchy of Nassau from its establishment in 1806 as part of the Confederation of the Rhine (jointly with Nassau-Usingen until 1816). The last reigning Duke, Adolph, became Duke of Nassau in August 1839, following the death of his father William. The Duchy was annexed to Prussia in 1866 after Austria's defeat in the Austro-Prussian War. From 1815 to 1839, Grand Duchy of Luxembourg was ruled by the kings of the Netherlands as a province of the Netherlands. Following the Treaty of London (1839), the Grand Duchy of Luxembourg became independent but remained in personal union with the Netherlands. Following the death of his sons, the Dutch king William III had no male heirs to succeed him. In the Netherlands, females were allowed to succeed to the throne. Luxembourg, however, followed Salic law which barred females from succession. Thus, upon King William III's death, the crown of the Netherlands passed to his only daughter, Wilhelmina, while that of Luxembourg passed to Adolph in accordance with the Nassau Family Pact. Adolph died in 1905 and was succeeded by his son, William IV. and from 1890 the Grand Duchy of Luxembourg. The branch of Nassau-Weilburg ultimately became rulers of Luxembourg. Counts of Nassau-Weilburg (1344–1688), Princely counts of Nassau-Weilburg (1688–1816) and Dukes of Nassau (1816–1866) Grand Dukes of Luxembourg (from the House of Nassau-Weilburg) - 1890–1912 and succession through a female onwards 1890–1905: Adolphe 1905–1912: William IV 1912–1919: Marie-Adélaïde 1919–1964: Charlotte 1964–2000: Jean 2000–present: Henri Counts of Merenberg Count of Merenberg (German: Graf von Merenberg) is a hereditary title of nobility that was bestowed in 1868 by the reigning Prince of Waldeck and Pyrmont, George Victor, upon the morganatic wife and male-line descendants of Prince Nikolaus Wilhelm of Nassau (1832–1905), younger brother of Adolf, last Duke of Nassau/Grand Duke of Luxembourg. Nicholas married Natalia Alexandrovna Pushkina (1836–1913), former wife of Russian general Mikhail Leontievich von Dubelt. In 1907 Grand Duke Adolph declared the family non-dynastic/morganatic. Had they not been excluded from the succession, they would have inherited the headship of the house in 1912. Georg Nickolaus would have thus become the reigning Grand Duke of Luxembourg.