Grand Duke Guillaume, 43, takes over from his father Henri, 70, who had served for 25 years in a largely symbolic role. The new grand duke will shortly greet the public from a balcony of the Grand Ducal Palace with the royal family at his side. Later on Friday, the new grand duke will host an evening gala for guests including French President Emmanuel Macron and German President Frank-Walter Steinmeier. LUXEMBOURG (AP) — Luxembourg’s Grand Duke Henri abdicated his throne on Friday in favor of his son, Guillaume. Later on Friday, the new grand duke will host an evening gala for guests including French President Emmanuel Macron and German President Frank-Walter Steinmeier.