In 1964, she converted to Catholicism and married the then-Prince Carlos Hugo of Bourbon-Parma in a Catholic ceremony in Rome, thus forfeiting her place in the royal succession.

Since their 1981 divorce, she has espoused left-wing causes, including anti-nuclear campaigns, and has developed a pantheistic philosophy about the relationship between man and nature.

[4][5] Because of the invasion of the Netherlands by Nazi Germany during World War II the Dutch royal family first fled to the United Kingdom.

Irene was not yet a year old when the family was forced to leave the Netherlands; she was christened in the Chapel-Royal of Buckingham Palace in London, with the wife of King George VI, Queen Elizabeth, being one of her godparents.

[6][7][8] Princess Juliana and her daughters again took flight when the London Blitz began, this time to exile in Ottawa, Canada, where her younger sister, Margriet, was born and where Irene attended Rockcliffe Park Public School.

[12] The first time the public or the royal family knew about the conversion was when a photograph appeared on the front page of an Amsterdam newspaper showing the Princess kneeling to receive communion at a Mass in the Roman Catholic Church of the Hieronymites (Los Jerónimos) in Madrid.

[18][19] Fresh memories of Francisco Franco's association with fascism amplified the crisis over a royal conversion to Catholicism and a marriage without approval of the Dutch States-General.

For the second in line to the throne to not only convert to Roman Catholicism, but to also associate with an alleged Franco sympathizer, caused shock and consternation in the Netherlands.

When Princess Irene left the Netherlands to join Prince Carlos in Paris after the announcement of their engagement, a threat was telephoned to KLM Royal Dutch Airlines by an anonymous caller saying, "you should investigate the plane".

It seemed to work and the Queen went on Dutch radio to tell the citizens that Princess Irene had agreed to cancel her engagement and was returning to the Netherlands.

When the airplane arrived at Schiphol Airport, the Princess was not on it, and Queen Juliana and her husband, Prince Bernhard were supplied with a Dutch military plane to go to Spain to retrieve their daughter.

[12][23] When the meeting ended in the early hours of the morning on Sunday, 9 February 1964, Dutch radio broke its traditional Sabbath day silence to announce that Princess Irene would give up any rights of succession to the throne so she could marry Carlos Hugo.

[31] Dutch television provided coverage of the marriage and Irene's family was among those who watched the ceremonies, although fate conspired in the form of a power failure which made them unable to see the last part of the rite.

[37] Prince Carlos Hugo was allowed to return in late 1977, but Princess Irene was not permitted back in the country until April 1978.

[42][43] Her youngest sister, Princess Christina, later waived her rights to the throne when she married Jorge Guillermo, a United States citizen born in Cuba and a Roman Catholic.

[45] In 1983 and 1985, she publicly spoke out against the additional deployment of NATO missiles at a large anti-nuclear rally in The Hague and with a letter to the newspaper De Volkskrant.

[48] The book outlined her philosophy that human beings are alienated from the natural world, but the Dutch media seized upon passages that recounted conversations she said she had with the trees and dolphins.