Amsterdam, Netherlands ? Prince Claus, the German-born husband of Queen Beatrix who employed wit, charm and patience to overcome Dutch hostility and win the affection of his adopted nation, died Sunday. He was 76.

Claus had been in and out of intensive care for several months with respiratory and heart problems. Doctors at the Academic Medical Center in Amsterdam said he died of Parkinson’s disease and pneumonia, according to a government statement.

He was admitted to the hospital’s intensive care unit two weeks ago with a lung infection. He had been fitted with a pacemaker over the summer.

Claus’ marriage to Beatrix, 64, was initially resisted by the Dutch public, with many residents upset about his service with the Nazi army in World War II and membership in the Hitler Youth.

But his eventual acceptance was reflected on Sunday, when the country’s TV and radio stations interrupted regular programming to air special newscasts and documentaries on Claus’ life. The government declared a period of mourning and instructed public buildings to fly flags at half-staff until his burial.

Funeral arrangements were not immediately announced.

In a live televised broadcast, Prime Minister Jan-Peter Balkenende said Claus’ death “comes as a shock to us all, even though we knew for years of his poor health.”

“He was a remarkable man who won a warm place in the hearts of the Dutch people,” Balkenende said. “With his passing, a great man is gone.”

Mourners young and old streamed to the Huis ten Bosch palace in The Hague to lay flowers or light candles outside the royal residence.

Claus’ entry into Dutch society despite his past was helped when he and the queen produced the first male heir to the Dutch throne in nearly a century, Crown Prince Willem Alexander. The royal couple had two more sons, Princes Johan Friso and Constantijn.

Prince Claus, the German-born husband of Dutch Queen Beatrix, is seen with Princess Maxima in this file photo from Oct. 24, 2001, in the Municipal Museum in The Hague, Netherlands. Claus died Sunday after battling ill health for years. He was 76.

Claus won over the Dutch people with his gentle wit and affable manner. He also made a favorable impression by mastering the Dutch language and learning to speak it with little trace of an accent.

He appeared frail during one of his last television appearances in March 2001 when he and the queen announced the engagement of Willem Alexander to Argentinian investment banker Maxima Zorreguieta. Claus advised his prospective daughter-in-law to learn the Dutch language and customs, as he had done 35 years earlier.

Though born a German aristocrat, Claus showed a humility that appealed to the unassuming Dutch. In 1997, he asked the public to refrain from marking his birthday because it coincided with the funeral of Britain’s Princess Diana.

Claus was born Sept. 6, 1926, in Dotzingen in northern Germany. Like many German secondary school children from aristocratic families, he joined the Nazi youth organizations Jungvolk and Hitlerjugend. After finishing school in 1944, he served with the German army in Denmark and with the 90th Panzer Division in Italy, but didn’t see combat.

He was captured by U.S. forces near Merano, Italy, in 1945 and sent to a prisoner of war camp. Later he was transferred to Britain, where he worked as a driver and interpreter.