BU Mint Set

Guillaume was born on 11 November 1981 as the eldest son of Grand Duke Henri and Grand Duchess Maria Teresa. After his father took office in 2000, he became Hereditary Grand Duke and thus the designated successor. In this capacity, he assumed representative duties and took part in economic missions and engagements at home and abroad. He has been married to Stéphanie de Lannoy since 2012. The couple has two sons; the elder, Prince Charles, is first in line to the throne.

The transition at the head of state was prepared gradually. In October 2024, Grand Duke Henri appointed Guillaume as his representative. This enabled him to assume part of the constitutional duties already. Henri’s abdication and Guillaume’s swearing-in took place on 3 October 2025. Before the Chamber of Deputies (Abgeordnetenkammer), the new Grand Duke took the oath prescribed by the Constitution.

Luxembourg is a parliamentary democracy in the form of a constitutional monarchy. The Grand Duke formally appoints the Prime Minister and the other members of the government, promulgates laws and represents the state. However, political decision-making authority lies with the elected Chamber of Deputies (Abgeordnetenkammer) and the government responsible to it. The actions of the head of state are bound by the constitutional framework.

The monarchy is also connected with the emergence of modern Luxembourg. The country was elevated to a grand duchy in 1815 and was initially linked to the Dutch royal house in a personal union. Since 1890, it has had its own dynastic line. Changes of sovereign are therefore treated not only as family events but also as constitutional acts of state.

Dynastic occasions regularly appear on Luxembourg’s euro coins. The image of the respective Grand Duke is a permanent element of the national coin design. The 2026 issue thus continues an established tradition while also documenting the change of the head of state depicted on Luxembourg’s coins.