Spain's new King, Felipe VI; his wife Queen Letizia; Princess Sofia; and Princess Leonor (l.) appear on the balcony of the Royal Palace in Madrid, June 19, 2014. Felipe VI, was sworn in during a low-key ceremony which monarchists hope will usher in a new era of popularity for the troubled royal household. Andrea Comas/Reuters
Spain's King Felipe VI and his wife Queen Letizia parade through the streets of Madrid from the Congress of Deputies to the Royal Palace, June 19, 2014. Gonzalo Fuentes/Reuters
Dutch King Willem-Alexander and his wife Queen Maxima, arrive at the Nieuwe Kerk or New Church in Amsterdam, The Netherlands, prior to the inauguration of King Willem-Alexander, April 30, 2013. Carl Court/AP
Belgium's King Albert II (r.) speaks with Queen Paola as they sit on a bench on the grounds of the Royal Palace in Laeken, Belgium, Sept. 2, 2012. Belgian King Albert unexpectedly announced in a national TV address on July 3, 2013, that he will step down in the near future. Virginia Mayo/AP
Belgium's Crown Princess Mathilde and Crown Prince Philippe watch the traditional military parade on National Day in front of the Royal Palace in Brussels, July 21, 2012. Yves Herman/Reuters
Swaziland's King Mswati III (c.) and Zulu King Goodwill Zwelithini (l.) attend the annual reed dance in Ludzidzini, Swaziland, in 2005, where young girls perform a dance after days of gathering reeds to present to the king. The annual reed dance gives Mr. Mswati the opportunity to choose another wife should he so wish. Siphiwe Sibeko/AP
Britain's Queen Elizabeth views the interior of the refurbished East Wing of Somerset House at King's College in London February 29, 2012. She is celebrating her sixtieth anniversary as Regent in 2012. Eddie Mulholland/Reuters
Thailand’s King Bhumibol Adulyadej is the world’s richest and longest reigning monarch - 65 years in June. He heads a constitutional monarchy. In September 2006, a coup was launched by several powerful Army generals with the avowed aim of “protecting the monarchy” against democratically elected populist Prime Minister Thaksin Shinawatra.
Shinawatra Sukree Sukplang /Reuters
Spain’s popular King Juan Carlos is the official head of state, but never intervenes publicly in politics. (L. to r.) Spain's Princess Letizia, Prince Felipe, King Juan Carlos, and Queen Sofia attend the Pascua Militar annual Christmas military parade at the Royal Palace in Madrid. Victor R. Caivano/AP
In Japan, monarchy is traditional, ceremonial, and without a hint of actual governing power. Emperor Akihito (l.) and Empress Michiko make a public appearance as well-wishers wave Japanese flags during New Year celebrations at the Imperial Palace in Tokyo Jan. 2. Issei Kato/Reuters
The world’s most potent monarchy, the House of Saud presides over vast oil reserves as well as Mecca, the holiest site in Islam. Saudi Arabia's King Abdullah bin Abd al-Aziz, (l.) and his family are absolute rulers. Here he speaks with his brother Prince Salman bin Abdel Aziz (r.) AP/File
The Swedish Royal family (l.-r.) Prince Daniel, Chris O'Neill, Princess Estelle, Crown Princess Victoria, Princess Madeleine, King Carl Gustaf, Prince Carl Philip, and Queen Silvia pose for a family photo during the Swedish National Day celebrations at the Royal Palace in Stockholm, June 6, 2013. Maja Suslin/Scanpix/Reuters
Queen Silvia and King Carl Gustaf of Sweden, arriving at the King's dinner for the Nobel Laureates at the Royal Palace in Stockholm in December, are among the remnants of European monarchy. Across Europe, monarchies became casualties of World War I, swept away as a new political order was fashioned from the continent’s killing fields. AP
Cambodia's King Norodom Sihamoni greets officials on the first day of the annual water festival along the Tonle Sap river in Phnom Penh November 20, 2010. Chor Sokunthea/Reuters
Malaysian King Sultan Abdul Halim Mu'adzam Shah (l.), delivers the opening speech as Queen Haminah Hamidun listens during the opening of a parliament session at the Parliament House in Kuala Lumpur, Malaysia, Monday, March 12, 2012. Lai Seng Sin/AP/File
A member of the Jordanian Independent Electoral Commission, walks past a large photograph of King Abdullah II of Jordan, at the counting votes station in Amman, Jordan, Jan. 24, 2013. Mohammad Hannon/AP
Morocco's King Mohammed VI (r.) is flanked by his brother prince Moulay Rachid, and Tunisian President Moncef Marzouki (l.), as they review the royal guard at Rabat airport Wednesday, Feb 8, 2012. Azzouz Boukallouch/Moroccan Royal Palace/AP/File
Britons are digesting new revelations that the king-in-waiting lobbied government ministers over policies on education, the environment, and healthcare.
ByMian Ridge, Correspondent
He has long been known to have strong opinions and a desire to publicly air them. Now a BBC Radio 4 documentary has revealed how Prince Charles has used his position to try and influence government policy, sometimes on topics he had not publicly expressed a view on.