On Friday, October 3, 2025, the Grand Duchy of Luxembourg will enter a new chapter in its history. After nearly 25 years as the reigning sovereign and Head of State, His Royal Highness Grand Duke Henri of Luxembourg will abdicate the throne in favor of his eldest son and heir, His Royal Highness Hereditary Grand Duke Guillaume of Luxembourg.

At ten o’clock in the morning, Grand Duke Henri will sign the Act of Abdication at the Palais Grand-Ducal. One hour later, Hereditary Grand Duke Guillaume will take the constitutional oath before the Chambre des Députés, formally becoming the reigning sovereign of the Grand Duchy of Luxembourg.

The ceremonies will mark the sixth transition of power since the House of Nassau-Weilburg began its reign in Luxembourg in 1890, continuing one of Europe’s lesser-known but enduring dynastic traditions.

Long before Luxembourg became Europe’s last reigning Grand Duchy, its story began on a rocky promontory overlooking the Alzette River. In the year 963, Count Siegfried acquired the small fortress known as Lucilinburhuc, the Little Castle, which gave the country its name. From this stronghold grew a county, and eventually a duchy, whose rulers would shape European politics for centuries.

The medieval House of Luxembourg produced four Holy Roman Emperors and several kings, extending their influence far beyond the borders of their small homeland. But as the centuries passed, dynasties shifted, wars redrew borders, and the territory of Luxembourg gradually diminished.

By the early 19th century, after the upheaval of the Napoleonic wars, Luxembourg’s future was decided at the Congress of Vienna in 1815. The settlement created the Grand Duchy of Luxembourg, placed in personal union with the King of the Netherlands. For seventy-five years, the Dutch monarchs held both crowns. That arrangement ended in 1890 with the death of King William III, when the Dutch throne passed to his daughter Wilhelmina, but Luxembourg, governed under Salic law, required a male heir. The succession passed to Adolphe, Duke of Nassau, beginning the Nassau-Weilburg line in Luxembourg.

Grand Duke Adolphe was succeeded by his son, Grand Duke William IV, whose six daughters posed a challenge for succession. His eldest, Marie-Adélaïde, became Luxembourg’s first reigning Grand Duchess in 1912, but abdicated in 1919 in favor of her sister Charlotte. Her Royal Highness Grand Duchess Charlotte of Luxembourg reigned for nearly half a century. During World War II, she and her family went into exile, but her BBC radio broadcasts became a rallying point for national resistance.

In 1964, she abdicated in favor of her son, His Royal Highness Hereditary Grand Duke Jean of Luxembourg. He reigned until 2000, when he abdicated the throne in favor of his son, His Royal Highness Grand Duke Henri of Luxembourg.

Guillaume Jean Joseph Marie, Prince of Luxembourg, Prince of Nassau and Bourbon-Parma, was born on November 11, 1981, at the Maternité Grande-Duchesse Charlotte in Luxembourg City. He is the eldest child of Their Royal Highnesses Grand Duke Henri and Grand Duchess Maria Teresa of Luxembourg and has held the title of His Royal Highness Hereditary Grand Duke of Luxembourg since his father’s accession in 2000.

Raised at Château de Fischbach alongside his four siblings, Prince Félix, Prince Louis, Princess Alexandra, and Prince Sébastien, Prince Guillaume grew up with a strong sense of duty to his country and family.

As a child, he attended primary school at the Lycée Robert Schuman in Luxembourg City. At the age of 16, he continued his studies in Switzerland, first at the Institut Le Rosey and later at the Collège Alpin Beau Soleil, where he obtained his French Baccalaureate in 2001.

In September 2001, now known as Hereditary Grand Duke Guillaume, he enrolled at the Royal Military Academy Sandhurst in England, where he successfully completed his officer training, graduating on August 9, 2002. He later studied international politics in the United Kingdom before continuing his university education in France. In 2009, he graduated with honours from the Université d’Angers with a degree in Literature and Political Science. He is fluent in Luxembourgish, French, German, Spanish, and English.

In 2004, Hereditary Grand Duke Guillaume first met Countess Stéphanie de Lannoy, a member of one of Belgium’s oldest noble families, at a gathering in Germany through mutual friends. The two reconnected at a party in 2009, and their relationship soon developed.

On April 26, 2012, the Maison du Grand-Duc officially announced their engagement. Days later, the press was invited to Château de Berg in Colmar-Berg to meet the newly engaged couple.

On October 19, 2012, Hereditary Grand Duke Guillaume and Countess Stéphanie de Lannoy, were married in a civil ceremony at the Hôtel de Ville in Luxembourg City, presided over by then-Mayor Xavier Bettel, who today serves as Deputy Prime Minister of the Grand Duchy of Luxembourg. On October 20, 2012, the couple held their Catholic wedding ceremony at the Cathédrale Notre-Dame du Luxembourg, with Archbishop Jean-Claude Hollerich presiding.  The beautiful wedding was attended by royals from around the world and marked the last royal wedding of an heir to a reigning European throne for quite some time, as the next generation of heirs, hence at the time second in line to a European throne, were still children.

On May 10, 2020, the Hereditary Grand Ducal couple welcomed their first child, Charles Jean Philippe Joseph Marie Guillaume, Prince of Luxembourg, Prince of Nassau and Bourbon-Parma. Their second son, François Henri Luis Marie Guillaume, Prince of Luxembourg, Prince of Nassau and Bourbon-Parma, was born on March 27, 2023.

On June 23, 2024, during Luxembourg’s National Day celebrations at the Philharmonie Luxembourg, Grand Duke Henri delivered his traditional speech. In it, he announced that he had decided to appoint his eldest son and heir, Hereditary Grand Duke Guillaume, as Lieutenant Representative, entrusting him with exercising many of the sovereign’s constitutional powers.

In his speech, the Grand Duke said:
“As we prepare for the future, the time has come to involve the Hereditary Grand Duke more closely in the exercise of my constitutional powers. In agreement with the government, I have decided to appoint him Lieutenant Representative in the coming months.”

According to Chapter 3, Section 2, Article 58 of the Constitution of the Grand Duchy of Luxembourg: “The Grand Duke may be represented by a person who meets the conditions of Article 56, paragraph 1, and who bears the title of Lieutenant-Representative of the Grand Duke. The Lieutenant-Representative of the Grand Duke only takes office after having taken the following oath before the Chambre des Députés.”

On October 8, 2024, at the Palais Grand-Ducal, Grand Duke Henri signed the Grand Ducal Decree of Appointment in the presence of the Prime Minister of the Grand Duchy of Luxembourg, Luc Frieden, Her Royal Highness Grand Duchess Maria Teresa, and Their Royal Highnesses Hereditary Grand Duke Guillaume and Hereditary Grand Duchess Stéphanie.

The decree set out the powers delegated by Grand Duke Henri to Hereditary Grand Duke Guillaume, carrying the same legal effect as if exercised by the sovereign himself.

Following the signing of the Grand Ducal Degree of Appointment, Hereditary Grand Duke Guillaume arrived at the Chambre des Députés to take the traditional oath before parliament, the first time the ceremony had been held in the Chambre des Députés, following constitutional reforms adopted in 2023. 

After a speech from the President of the Chambre des Députés, Claude Wiseler, Hereditary Grand Duke Guillaume then rose, took the oath, and pledged: “I swear to observe the Constitution and the laws and to faithfully fulfill my constitutional duties.”

This appointment placed Hereditary Grand Duke Guillaume in line with his predecessors who had taken the same step: Prince Henry of the Netherlands in 1850, William IV in 1902, Grand Duchess Marie-Adélaïde’s mother, Grand Duchess Marie-Anne, in 1908, Hereditary Grand Duke Jean in 1961, and Hereditary Grand Duke Henri in 1998. In each case, the role served as the final preparation for the throne.

For Hereditary Grand Duke Guillaume, it was the last step on his path from heir to sovereign.

On December 24th, 2024, during his annual Christmas message, Grand Duke Henri announced that he would abdicate the throne in favor of his son, Hereditary Grand Duke Guillaume.

In his speech, the Grand Duke said:
“When I look back today, after almost 25 years, I do so with deep gratitude and humility. It has been a period during which Luxembourg has made much progress, and I am pleased to have been able to be part of that journey with you, together with the Grand Duchess.”

At the end of his speech, he confirmed his decision:
“Today, the Grand Duchess and I are pleased to share with you that Hereditary Grand Duke Guillaume and Hereditary Grand Duchess Stéphanie will succeed us on October 3rd, 2025. I know that they will do their utmost to contribute to the well-being of our country.”

The abdication comes just days before what would have been Grand Duke Henri’s Silver Jubilee, marking exactly 25 years on the throne.

With Hereditary Grand Duke Guillaume’s accession to the throne as the new Grand Duke of Luxembourg, his wife will be known as Her Royal Highness Grand Duchess Stéphanie of Luxembourg, and their eldest son, Charles, will be known as His Royal Highness Hereditary Grand Duke Charles of Luxembourg.  He will also be the youngest heir to a European throne, followed by His Serene Highness Hereditary Prince Jacques of Monaco.  

For the Grand Duchy of Luxembourg, Friday’s historic Change of Throne will mark the passing of responsibilities from one generation to the next, continuing a fascinating dynastic tradition that has shaped the beautiful country for more than a century.