Otto von Habsburg (RIP)

Otto von Habsburg, who has died aged 98, bore the oldest and most eminent dynastic name in European history and could, according to genealogists, trace his ancestry back to the sixth century. The pretender to the defunct thrones of Austria, Hungary, Croatia and Bohemia (now part of the Czech Republic), he pursued a democratic postwar career as a member of the European parliament and a fervent advocate of European union.

Spending time in German diplomatic and political circles, as I once did as a correspondent, you meet men who introduce themselves in the formal German manner – a brief bow from the shoulders followed by an unadorned name straight out of Germanic history. But I never quite got used to shaking hands with a stranger who flatly introduced himself as "Bismarck" (diplomat), "Hannover" (banker) or "Rommel" (mayor of Stuttgart). Or indeed "Habsburg", whom I met briefly at a party conference in Munich.

Franz Joseph Otto Robert Maria Anton Karl Max Heinrich Sixtus Xavier Felix Renatus Ludwig Gaetan Pius Ignatius von Habsburg was born at Reichenau an der Rax, Lower Austria. His father, Charles, would become Emperor of Austria and King of Hungary. Otto's mother was Zita of Bourbon-Parma. His great-uncle, Archduke Franz Ferdinand, whose assassination in 1914 would trigger the first world war, stood in for Otto's ancient godfather, the Emperor Franz Joseph, at his christening. Otto's father succeeded Franz Joseph in 1916, whereupon Otto became crown prince.

Otto von Bismarck had excluded Austria-Hungary from his united Germany of 1871 because of its large and diffuse non-German population. After 1918, it duly broke up into independent states including Czechoslovakia and Hungary. The rump of ethnically German Austria became a republic too. Charles went into exile with his family that year, and they later moved to the Basque country, Belgium and France. In 1919 Austria finally dispossessed the Habsburgs, although they kept their private fortune. Charles died in Madeira in 1922, whereupon Otto became head of the house of Habsburg, the titular Duke of Lorraine and pretender to four thrones, at the age of nine.

Noble titles confer no status or privilege in the four republics of which Habsburg held citizenship, but while Germany – where he spent most of his later life – tolerates their use, in Austria they are banned by law. So in the country of his birth, the eldest son of the last emperor of Austria was officially styled Otto Habsburg-Lothringen (Lorraine) – even the simple aristocratic prefix "von" was outlawed. Habsburg, always a loyal Catholic working for better understanding among Christians, Jews and Muslims, went to the Catholic University of Leuven, in Belgium, to read politics and social studies. He graduated in 1935.

Still believing in his right to the throne, Habsburg as an Austrian patriot opposed the country's absorption by Hitler into the Third Reich in 1938, and was sentenced to death by the Nazis. He fled France with his mother to neutral Portugal and then Washington DC in 1940, just before the Germans took Paris. After the war, Habsburg spent several years in France and Spain.

In May 1961, he formally renounced his claim to the Austrian throne and announced that he was a loyal citizen of the republic. As a result, two years later, an Austrian court lifted the ban on his visiting the land of his birth – a decision that proved unpopular in some quarters, precipitating the "Habsburg crisis" in Austrian politics. He was allowed to cross the border in 1966. Towards the end of his life, he admitted that his heart had not been in the renunciation, which he made out of sheer pragmatism.

Taking up residence in Germany, whose citizenship Habsburg also held, he joined the Christian Social Union (CSU), the rightwing Bavarian sister party of the Christian Democratic Union party (CDU), active in the rest of Germany. He was elected to the European parliament for the CSU and sat for 20 years from 1979 as MEP for Bavaria, becoming the equivalent of "father of the house" as the oldest member. He was already president of the international Pan-Europa Union from 1973, retiring only in 2004, strongly favouring political union and the eastward expansion of the EU to countries once ruled by his ancestors. In 1988, Habsburg clashed with the Rev Ian Paisley, then an MEP, after Paisley called the visiting Pope John Paul II the antichrist. A year later Habsburg helped to organise the "pan-European picnic" on the Austrian-Hungarian border in the summer of 1989, one of the events that led to the fall of the Berlin Wall and the collapse of Soviet communism.

He married the German Princess Regina of Saxe-Meiningen in 1951; she died in 2010. They lived near Lake Starnberg in Bavaria and had five daughters and two sons, who survive him. The eldest son, Karl, becomes head of the house of Habsburg.