The royal marriage that required a Queen's permission to be valid

Countries & Cities · Published 12 October 2026 Swipe more like this →

In short: When Princess Caroline of Monaco married Prince Ernst August of Hanover in 1999, the union wasn't just a local affair. Because of a specific British law regarding royal lineages, the marriage required the formal consent of Queen Elizabeth II to be legally recognized in the United Kingdom.

The legal complexity of Caroline’s third marriage stems from her husband's lineage. Prince Ernst August is a descendant of George II and a distant cousin of Queen Elizabeth II. Because his family owned substantial property in the UK and he held dual citizenship, he was subject to the Royal Marriages Act 1772. This act mandated that certain members of the royal family obtain the monarch's consent before marrying, otherwise, the union would be considered void under British law. The Prince's family lost their sovereign status in 1866. He is a legitimate male-line descendant of George II. His first wife was Chantal Hochuli. He also has two sons from that previous marriage.

To ensure the marriage was valid in Britain, Queen Elizabeth II issued an Order in Council on January 11, 1999, just before the wedding. While the Act was eventually repealed in 2015, its existence highlights the enduring reach of British constitutional law over international royal houses. Although the title of Duke of Brunswick is honorific—having been stripped by the Weimar Republic in 1918—Monaco continues to recognize the Hanoverian royal titles and styles. The couple shares Queen Victoria as a common ancestor. Caroline was born in 1957. She is the elder sister of Prince Albert II.

Caroline's life has been defined by these intricate layers of nobility and public service. As the eldest child of Rainier III and Grace Kelly, she served as the heir presumptive to the Monegasque throne for much of her life. Beyond the palace, she has established significant cultural institutions, including the Médiathèque Caroline, which transitioned into a 'free for all' community center in 2025 to provide universal cultural access. She was a UNESCO Goodwill Ambassador starting in 2003. She founded the Jeune J'écoute youth hotline in 1981. She also founded the Les Ballets de Monte Carlo. She earned a diploma in philosophy from the Sorbonne University.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• The legal battle behind the royal wedding of Charles and Camilla in 2005
• A royal marriage so disastrous it nearly toppled the British government in 1820
• The royal princess who was almost the British bride
• How a strategic marriage paved the way for the British Hanoverian royal dynasty
• The princess who traded the British throne for a Catholic faith
• The princess who lived in a royal "Nunnery" out of fear
• The longest-lived princess of the blood royal lived through four British monarchs
• The invisible operating system powering hundreds of millions of cars across the globe
• Raccoon City: How a fictional Midwestern hamlet became the epicenter of a global apocalypse
• Why Prince Louis represents a historic shift in British royal succession rules
• The Range Rover was never meant to be a luxury status symbol
• The Royal Life and Sudden Death of Prince George, Duke of Kent

More in UK & Ireland: places · More in Countries & Cities · Latest · A–Z · All topics