House of Nassau

House of Nassau
Armorial of the House of Nassau Azure billetty or, a lion rampant of the last armed and langued gules
Country	Germany, Netherlands, Belgium, France, England, Scotland, Ireland, Luxembourg, Nassau, Orange
Founded	c. 1093
Founder	Dudo of Laurenburg
Current head	Henri, Grand Duke of Luxembourg (in cognatic line)
Titles	King of the Romans King of the Netherlands King of England, Scotland and Ireland Grand Duke of Luxembourg Duke of Nassau Duke of Limburg Prince of Orange Prince of Orange-Nassau Prince of Nassau-Orange-Fulda Prince of Nassau-Usingen Prince and Count of Nassau-Weilburg Prince and Count of Nassau-Dietz Prince and Count of Nassau-Siegen Prince and Count of Nassau-Hadamar Count of Nassau Count of Laurenburg Count of Nassau-Dillenburg Count of Nassau-Wiesbaden-Idstein Count of Nassau-Saarbrücken Stadtholder in the Netherlands
Estate(s)	Nassau Castle
Dissolution	1985 (1985) (in agnatic line after death of Grand Duchess Charlotte)
Cadet branches	Nassau-Weilburg Orange-Nassau Nassau-Corroy (illegitimate)

The House of Nassau is the name of a European aristocratic dynasty. The name originated with a lordship associated with Nassau Castle, which is located in what is now Nassau in Rhineland-Palatinate, Germany. With the fall of the Hohenstaufen dynasty in the first half of the 13th century, royal power within Franconia evaporated and the former stem duchy fragmented into separate independent states. Nassau emerged as one of those independent states as part of the Holy Roman Empire. The lords of Nassau were originally titled "Counts of Nassau", subject only to the Emperor, and then elevated to princely rank as "Princely Counts". Early on, the family divided into two main branches – the elder (Walramian) branch, which gave rise to the German king Adolf, and the younger (Ottonian) branch, which gave rise to the Princes of Orange and the monarchs of the Netherlands.

At the end of the Holy Roman Empire and the Napoleonic Wars, the Walramian branch had inherited or acquired all the Nassau ancestral lands and proclaimed themselves, with the permission of the Congress of Vienna, the "Dukes of Nassau", forming the independent state of Nassau (with its capital at Wiesbaden). This territory now mainly lies in the German Federal State of Hesse, and partially in the neighbouring State of Rhineland-Palatinate. The Duchy was annexed by Prussia in 1866 after the Austrian-Prussian War as an ally of Austria. It was subsequently incorporated into the newly created Prussian Province of Hesse-Nassau.

Today, the term Nassau is used in Germany as a name for a geographical, historical and cultural region, but no longer has any political meaning. All Dutch and Luxembourgish monarchs since 1815 have been senior members of the House of Nassau. However, in 1890 in the Netherlands and in 1912 in Luxembourg, the male lines of heirs to the two thrones became extinct, so that since then, they have descended in the female line from the House of Nassau.

According to German tradition, the family name is passed on only in the male line of succession. The House would therefore, from this German perspective, have been extinct since 1985.^[1][2] However, both Dutch and Luxembourgish monarchial traditions, constitutional rules and legislation in that matter differ from the German tradition, and thus neither country considers the House extinct. The Grand Duke of Luxembourg uses "Duke of Nassau" as his secondary title and a title of pretense to the dignity of Chief of the House of Nassau (being the most senior member of the eldest branch of the House), but not to lay any territorial claims to the former Duchy of Nassau (which is now part of the Federal Republic of Germany).