On 4 July 2011, Otto von Habsburg, also known as Otto of Austria, former head of the House of Habsburg and Sovereign of the Order of the Golden Fleece (1922–2007) and former Crown Prince (1916–1918) and, by pretense, Emperor-King (from 1922), of Austria-Hungary, died at 98 years of age. The following day, a 13-day period of mourning started in several countries formerly part of Austria-Hungary. Otto was entombed in the Imperial Crypt under the Capuchin Church in Vienna on 16 July and his heart buried in Pannonhalma Archabbey in Hungary on 17 July. Multiple requiems were celebrated. Many foreign dignitaries—among them reigning or former monarchs King Carl XVI Gustaf of Sweden, Henri, Grand Duke of Luxembourg, King Michael I of Romania, Tsar Simeon II of Bulgaria, Hans-Adam II, Prince of Liechtenstein, and Fra' Matthew Festing, Prince and Grand Master of the Order of Malta—attended the Requiem Mass in Vienna's St. Stephen's Cathedral on 16 July, presided over by Cardinal Christoph Schönborn, which was followed by the entombment in the Imperial Crypt. Commemorations were also held in Bavaria. This was the most recent burial of a royal Habsburg in the Imperial Crypt—following a centuries-old ceremony—where 145 other members of the House of Habsburg, among them many Holy Roman Emperors and Austrian Emperors, have been entombed since 1633. Around 1,000 invited guests and 100,000 members of the public attended the funeral in Vienna, which was broadcast live by Austrian Television. A funeral procession over one kilometer long brought Otto's coffin from St. Stephen's Cathedral to the Imperial Crypt. The ceremonies led to large parts of central Vienna being closed down for public traffic. The funeral has been described as the "last Emperor's funeral" to take place in Vienna. Reaction The eldest son of Charles I, the last Emperor of Austria and King of Hungary, and his wife, Zita of Bourbon-Parma, Otto was born as third in line to the thrones of Austria, Hungary, Croatia and Bohemia. With his father's ascent to the thrones in 1916, he was himself likely to become the Emperor. As his father never abdicated, Otto was considered by himself, his family and Austro-Hungarian legitimists to be the rightful Emperor-King. Forced to live in exile with his family after 1918, Otto was active on the Austrian and European political stage from the 1930s, as an early proponent of European integration and a fierce opponent of Nazism and communism. After