Die Schlosskirche in Weilburg (information on the crypt where some members of the Ducal House of Nassau and the Grand Ducal House of Luxembourg are buried)
The Crown of the Grand Duchy is hereditary in the Nassau family in accordance with the Pact of 30 June 1783, Article 71 of the Treaty of Vienna of 9 June 1815, and Article 1 of the Treaty of London of 11 May 1867.
The said Treaty of Vienna of 9 June 1815 Article 71 says, in English:
The right and the command of succession established between the two branches of the house of Nassau by the act of 1783, said Nassauischer Erbverein, are maintained and transferred from the four principalities of Orange-Nassau to the Grand Duchy of Luxembourg.