10 things to know about UK's newly crowned monarch King Charles III

Amy Haneline

King Charles has already been U.K.'s monarch for more than seven months – but his name became an even bigger talker Saturday when he was officially crowned king at a highly-televised coronation packed with pomp and circumstance.

Known as Prince Charles of Wales for years before ascending the throne, the son of Queen Elizabeth II and Prince Philip waited 70 years to become king. He sat next in the line of succession since he was 3 years old, making him the longest-serving and the most-prepared heir to the throne in British history. When the queen died Sept. 8, 2022, Charles immediately became king.

Here are 10 things to know about the king. 

WATCH LIVE:King Charles III's coronation live updates

He was crowned at his coronation on May 6

King Charles was formally crowded during a solemn religious ceremony, known as Operation Golden Orb, on May 6.

Following tradition, Charles was crowned with St. Edward's crown. The crown was made for King Charles II in 1661 as a replacement for a medieval crown that melted down in 1649. Charles' mother, Queen Elizabeth, wore the same crown at her 1953 coronation. 

Queen Consort Camilla was also crowned in a shorter and simpler ceremony. She was crowned with Queen Mary's crown, marking the first time an existing crown was used for the queen consort's coronation.

King Charles III formally crownedA recap of the monarch's coronation day

King Charles III waves to the crowd during a visit to Germany in March 2023.

Charles became king immediately upon Queen Elizabeth II’s death

Born Nov. 14, 1948, Charles Philip Arthur George Windsor is the eldest son of Queen Elizabeth II and Prince Philip, who died April 9, 2021.

Charles became king the moment his mother died in September, meaning he immediately became head of state for the United Kingdom, Canada, Australia, New Zealand and a dozen other countries. He's also the titular head of the Church of England and head of the military and the judiciary, and he carries a host of other royal titles and duties.

The name he chose as his regnal, or reign, name is his own first name, Charles, and it is followed by the Roman numeral III because he is the third king Charles in British history.

He is the oldest monarch to ever take the British throne

Charles, now 74, was 73 when he became king, making him the oldest monarch to ever take the British throne. In comparison, Elizabeth was 25 when she became queen and reigned until her death at 96. She was the U.K.'s oldest monarch ever, and the longest-serving, surpassing her great-great-grandmother Queen Victoria, who reigned 63 years and died in 1901.

His eldest son Prince William is next in line for the throne

Prince William is next in line for the throne under the British line of succession, followed by his children with Princess KatePrince George, Princess Charlotte and Prince Louis. Prince Harry falls fifth in line after them.

Prince William and Princess Kate and their kids, Prince George, Princess Charlotte and Prince Louis, attend an Easter service in April 2023.

He was previously married to Princess Diana

Charles was first married to Lady Diana Spencer, later known as Princess Diana. They were married for 15 years from 1981 to 1996. Diana was 20 and Charles was 32 at the time of their nuptials. The wedding was billed as a fairy tale, but their married life was not. 

Britain's Prince Charles kisses his bride, Princess Diana, on the balcony of Buckingham Palace in London, after their wedding on July 29, 1981.

As the public would learn later, Charles had always been in love with Camilla, a woman he’d met over a decade prior in 1970. During the marriage of Charles and Diana, there were affairs on both sides.

The royal couple separated in 1992 and divorced in 1996 before Diana's death in 1997. 

He married Camilla in 2005

Charles married the former Camilla Parker Bowles in 2005 in two ceremonies in Windsor. She became known as Camilla, Duchess of Cornwall. She is now the queen consort and will be crowned alongside her husband on coronation day.

Legally, Camilla was the Princess of Wales when she married Charles in 2005 but it was decided at the time she would assume one of the Charles' lesser titles instead. Princess Diana long blamed Camilla for the breakup of her marriage to Charles (even though that wasn't all Camilla's doing) and public fury remained when Camilla and Charles married eight years after Diana's death in a car crash in Paris. 

Prince Charles and Camilla speak in the garden of Clarence House in London in February 2005.

Because of the controversy, few Brits thought the wedding would actually happen. Plus, a future king had never married a divorced woman. But by the couple's 10th wedding anniversary, public perception of Camilla began to change as the royal family, including the queen, embraced her. Charles once said she would never be called Queen Camilla when he assumed the throne. His wishes on that later changed, and Queen Elizabeth II made it official in February 2022 when she announced she wanted her heir's second wife to be known as queen consort.

Charles has three siblings

King Charles has a sister and two brothers. From oldest to youngest, they are Princess Anne, the Princess Royal, 72; Prince Andrew, the Duke of York, 62; and Prince Edward, Earl of Wessex, 58. They are all children of Queen Elizabeth and Prince Philip.

Princess Anne is a full-time working royal, currently 16th in line for the throne. She appears in line after her younger brothers because she was born before the Succession to the Crown Act of 2013, which ended the system of male primogeniture.

Before the rules changed, younger sons would displace an elder daughter in the line of succession. Now the succession is based on birth order, not gender: Thus, Princess Charlotte, 7, is now third in line and ahead of her younger brother Prince Louis, 4, who is fourth.

From left, King Charles, Princess Anne, Prince Andrew and Prince Edward, with Prince William and Prince Harry behind them, in procession during the state funeral Queen Elizabeth II at Windsor Castle on Sept. 19, 2022 in Windsor.

Prince Andrew is eighth in line for the throne despite his scandal-ridden history. He's been under fire in Britain since at least 2011 for his friendship with Jeffrey Epstein, the convicted American sex offender who died in jail in 2019. After a disastrous 2019 TV interview about his relationship with Epstein, Andrew officially stepped back from public duties and as a senior working royal. 

Earlier this year, Andrew settled a lawsuit with an American sexual assault accuser, Virginia Roberts Giuffre, who had been airing allegations against him publicly since 2015.

Charles' youngest brother, Prince Edward, is a full-time working royal and is 13th in line for the throne.

He was previously known as Prince of Wales

Charles is known for his long and steady service as the Prince of Wales, a role he carried out for nearly 60 years. He participated in official and ceremonial duties and established more than 20 charities, including The Prince's Trust, The Prince's Foundation and The Prince of Wales’s Charitable Fund.

As Queen Elizabeth's mobility waned in the months before her death, Charles stepped in for the monarch, including standing in for her for the first time at the state opening of Parliament, when he delivered what has long been called "the Queen's Speech." Now it will be called "the King's Speech."

He is interested in environmental causes

King Charles has shown keen interest in environmental causes including organic farming, architecture and urban planning and fighting climate change.

As the Prince of Wales, he attended the COP26 in 2021 and warned that the conference was "quite literally" the last chance to save the planet from the ravages of climate change.

"As the future of humanity and nature herself are at stake, it is surely time to set aside our differences and grasp this unique opportunity to launch a sustainable green recovery," Charles said.

However, Charles opted to skip COP27 in 2022 after becoming king, fueling speculation that he will have to rein in his environmental activism now that he has ascended the throne.

He served in the military

He served in the Royal Air Force and the Royal Navy in the 1970s, and he will no doubt be on hand for many military parades and events during his reign.

As king, Charles is expected to "slim down" the monarchy – reduce the number of working senior royals supported by taxpayers – and reduce the overall multimillion-pound annual cost of the royal show.

Read all our King Charles coronation coverage:

Biggest moments: Charles and Camilla crowned, royal family appears on balcony

The balcony:See who greeted the crowd with Charles and Camilla (not Harry)

King Charles III formally crowned: A recap of the monarch's coronation day

Queen Camilla looks regal: She is also crowned at King Charles III coronation

Prince Harry: Royal attends but misses balcony palace moment

Prince George, Princess Charlotte, Prince Louis: See the royal grandchildren on coronation day

Prince Harry and Prince William: Look back their complicated relationship

Coronation photos: See all the best photos from the ceremony and procession