The constitutional monarchy

A constitutional monarchy is a type of political regime that recognises a hereditary Monarch as Head of State. In Luxembourg, this title is given to the direct descendants of Grand Duke Adolphe, Duke of Nassau.

This section provides more information on the order of succession to the Throne in the event of death or abdication by the reigning Monarch, on the Regency in the event of the Grand Duke's temporary incapacity and on the Lieutenance, which allows the Grand Duke to delegate certain powers to his Lieutenant-Représentant.

Under the terms of Article 56 of the Constitution, 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 Congress of Vienna of 1815 granted perpetual possession of the Grand Duchy to the King of the Netherlands, William I, Prince of Orange-Nassau, and, on his death, to his successors. According to the Final Act of the Congress of Vienna, the order of succession established between the two branches of the House of Nassau by the Pact of 1783 also applies to the Grand Duchy of Luxembourg.While the first chapter of the Family Pact of 1783 describes the sovereign possessions of the House of Nassau, the second chapter is devoted to the order of succession. At that time, the Crown was transmitted according to Salic law in direct line by order of primogeniture to male descendants, excluding female descendants. In the absence of a male descendant in direct and collateral line in one of the branches of the House of Nassau, the Crown passed by right to the male descendants of the other branch. In the absence of male offspring in direct and collateral line in both branches, the Crown passed in order of primogeniture to the female offspring of the ruling dynasty.

The Treaty of London of 1867 redefined the status of the Grand Duchy. Napoleon III tried to acquire Luxembourg, but failed because of Bismarck's refusal to allow a former member of the German Confederation to fall under French rule. At the time, the City of Luxembourg was still occupied by a Prussian federal garrison. Following the 'Luxembourg Crisis', an international conference was organised in London to prevent a French-Prussian war. Prussia agreed to withdraw its garrison from the fortress of Luxembourg. The Grand Duchy was declared perpetually neutral. Article 1 of the treaty maintained the ties between the Grand Duchy and the House of Orange-Nassau and confirmed the rights that the agnates (the descendants by male links from a common male ancestor) of the House of Nassau have over the Grand Duchy.

The order of succession, as set down in the Family Pact, has been amended twice since then.

In 1906, Grand Duke Guillaume IV sensed that his health was worsening and that the question of who would succeed him would soon arise, since six daughters were born from his marriage to Maria Ana of Braganza. He therefore issued a new family statute to guarantee his daughters' succession to the throne. This statute was based on Article 42 of the Family Pact, which stipulated that after the extinction of all the male members of the House of Nassau, the female line of succession would come into play. The 1907 statute also stipulated that the younger princesses would be next in line if there were no male descendant of Grand Duchess Marie-Adélaïde. Princess Marie-Adélaïde was declared heir apparent to the Crown. This statute was submitted to the Chamber of Deputies, which gave it the force of law on 10 July 1907.

On 20 June 2011, by order of Grand Duke Henri, the Marshal of the Court announced a new internal regulation introducing absolute primogeniture to the order of succession within the House of Luxembourg-Nassau. This guarantees equality between men and women in terms of succession to the Throne. This new order of succession first applies to the descendants of Grand Duke Henri.

Currently, the succession to the throne is guaranteed by Prince Guillaume, the Crown Prince. His son, Prince Charles, is second in the order of succession.

The role of a Regent is to take on the function of Grand Duke if the latter is unable to perform them. The conditions for a Regent's appointment and its modalities are enshrined are laid down in the Constitution.

The Regent, who must in all cases be of age and a direct descendant of the Grand Duke Adolphe, Duke of Nassau, by order of primogeniture and representation, can only assume the duties of Head of State after taking the oath before the Chamber of Deputies.

• As specified in article 59 of the Constitution, there are various scenarios that can give rise to a Regency:In the event of death or abdication of the Head of State, if the successor is a minor, the Regency will be exercised until they come of age;
• In the event that the Grand Duke is temporarily unable to carry out his constitutional functions, the Regent will assume these functions on an interim basis.

So far, there have been two Regents in the Grand Duchy:

• Duke Adolphe of Nassau, later Grand Duke of Luxembourg, exercised the first two Regencies. His first Regency began at the end of the reign of King Grand Duke William III, from 8 April 1889 (he was sworn in on 11 April 1889) and ended on 3 May 1889. The second lasted only a short while, from 4 November 1890 (he was sworn in on 6 November 1890) to 23 November 1890, when King Grand Duke William III died.
• The other two Regencies were held by Grand Duchess Maria Ana, wife of Grand Duke Guillaume IV. She first became Regent during the final illness of Grand Duke Guillaume IV on 13 November 1908 (she was sworn in on 19 November 1908). It lasted until 25 February 1912 following the death of Guillaume IV. Her second Regency lasted from 25 February 1912 to 14 June 1912, while Grand Duchess Marie-Adélaïde was still a minor.

As the function of Head of State in the Grand Duchy of Luxembourg is hereditary, the Grand Duke may choose to be represented by a direct descendant of Grand Duke Adolphe, Duke of Nassau, according to the order of primogeniture and by representation. They will be given the title of Lieutenant-Représentant of the Grand Duke.

The latter will only be sworn in after taking the following oath before the Chamber of Deputies:

« Je jure d'observer la Constitution et les lois et de remplir fidèlement mes attributions constitutionnelles ». ('I swear to observe the Constitution and the laws and to faithfully fulfil my constitutional duties.')

The Grand Duke thus shares all or part of his powers with his Lieutenant-Représentant. The powers of the Lieutenant- Représentant are limited by this mandate and the measures that he takes by virtue of his mission have the same effect as if they had been issued by the Grand Duke himself.

Today, the Lieutenancy is considered to be the last stage in preparing the Hereditary Grand Duke to his future role as Head of State.

There have been six Lieutenancies in the history of the Grand Duchy:

• The first Lieutenancy was that of Prince Hendrik of the Netherlands, who was appointed by his brother, King Grand Duke William III, on 5 February 1850 (swearing-in on 24 October 1850). It lasted for almost 30 years, until Prince Hendrik's death on 13 January 1879.
• The second Lieutenancy was that of Prince Guillaume of Nassau, later Grand Duke Guillaume IV, who was appointed by his father, Grand Duke Adolphe, then 85 years old, as Lieutenant-Représentant on 4 April 1902 (swearing in on 14 April 1902). It ended with his accession to the Throne following Grand Duke Adolphe's death on 17 November 1905.
• The third Lieutenancy took place from 19 March 1908 (swearing-in on 2 April 1908) when Grand Duke Guillaume IV appointed his wife Grand Duchess Maria Ana as Lieutenant-Représentant due to his poor health. She remained Lieutenant until 13 November 1908, when she became Regent.
• The fourth Lieutenancy was that of Crown Prince Jean, appointed Lieutenant-Représentant of Grand Duchess Charlotte on 28 April 1961 (swearing in on 4 May 1961). It ended on 12 November 1964 with the abdication of Grand Duchess Charlotte in his favour.
• The fifth Lieutenancy was that of Crown Prince Henri, which started on 3 March 1998 (sworn in on 4 March 1998). This lasted until 7 October 2000, with the abdication of Grand Duke Jean in his favour.
• Finally, the sixth Lieutenancy began on Tuesday, 8 October 2024, when Crown Prince Guillaume was sworn in before the Chamber of Deputies, thus becoming Lieutenant-Représentant of the Grand Duke. This was the first time ever that a swearing in was held in the Chamber of Deputies, as required by the revised Constitution of July 2023.