Jean (Jean Benoît Guillaume Robert Antoine Louis Marie Adolphe Marc d'Aviano; 5 January 1921 – 23 April 2019) reigned as Grand Duke of Luxembourg from 1964 until his abdication in 2000. He was the first Grand Duke of Luxembourg of French agnatic descent.
Jean was the eldest son of Grand Duchess Charlotte and Prince Felix. Jean's primary education was initially in Luxembourg, before attending Ampleforth College in England. In 1938, he was officially named Hereditary Grand Duke as heir to the throne of Luxembourg. While Luxembourg was occupied by Germans during the Second World War, the grand ducal family was abroad in exile. Jean studied at the Université Laval in Quebec City. Jean later volunteered to join the British army's Irish Guards in 1942, and after graduating from the Royal Military Academy Sandhurst, received his commission in 1943. He participated in the Normandy landings and the Battle for Caen, and joined the Allied forces in the liberation of Luxembourg. From 1984 until 2000, he was colonel of the Irish Guards.
On 9 April 1953, Jean married Princess Joséphine Charlotte of Belgium with whom he had five children. On 12 November 1964, Grand Duchess Charlotte abdicated and Jean succeeded her as Grand Duke of Luxembourg. He then reigned for 36 years before he himself abdicated on 7 October 2000 and was succeeded by his son, Grand Duke Henri.
He is also known as Jean Benoît Guillaume Robert Antoine Louis Marie Adolphe Marc d'Aviano.
Surrounded by his family, Grand Duke Jean died at 00.25 CEST on 23 April 2019 at the age of 98 after he had been hospitalized for a pulmonary infection.
He had become the world's oldest living monarch by the time of his death.
His funeral was held on Saturday, 4 May at the Notre-Dame Cathedral, Luxembourg after a period of mourning of 12 days.