King Charles III Officially Crowned at Coronation Ceremony

King Charles III was formally crowned the monarch of the United Kingdom and Northern Ireland at his coronation today, the first such ceremony held since his late mother's coronation 70 years ago.

The crowning moment came after the royal participated in a procession from Buckingham Palace to Westminster Abbey, riding with Queen Camilla in the Diamond Jubilee State Coach pulled by six Windsor Grey horses.

What followed was a two-hour symbolic ceremony presided over by Archbishop of Canterbury Justin Welby. The historic event marked the 40th coronation to take place at Westminster Abbey, and was marked by firsts.

Bishop Sarah Mullally, who did a gospel reading, became the first female bishop from the Church of England to participate in a coronation.

A Black choir sang "Hallelujah," another attempt to show the greater inclusivity King Charles III has pledged.

Royal watcher Victoria Murphy pointed out to ABC News that the diversity of the audience was groundbreaking, saying, "We're going to see lots of women, which was not the case in 1953, people of different ethnicities, different religions. They’re really putting front and center the diversity that exists in Britain today.”

For the first time in history, the service featured moments in languages from around the U.K., including Welsh and Scottish Gaelic.

Among the guests at the service were the king’s sons Prince William and Prince Harry, First Lady Jill Biden; singers Lionel Richie and Katy Perry; acting legends Dames Judi Dench, Maggie Smith, Emma Thompson and Joanna Lumley; composer Sir Andrew Lloyd Webber; Spice Girl Mel B; designer Stella McCartney; and — in a break from the past — a large number of people selected for their good works, rather than for their royal blood.

William participated in his father’s coronation at times. He was there for the presentation of the robe and stole — whispering something to his father during the solemn moment — and later recited the Homage of Royal Blood. Leading the “words of fealty,” he said, “I, William, Prince of Wales, pledge my loyalty to you and faith and truth I will bear unto you, as your liege man of life and limb. So help me God.”

Harry, as a nonworking member of the royal family, did not participate. He wore a simple morning suit.

During the ceremony, Charles also took the legally required coronation oath to promise to maintain the Protestant faith, before he was privately anointed by Welby. The deeply religious moment is considered a private one between the sovereign, archbishop and God.

After the anointing, Charles received the crown jewels, orb, and two scepters so that "justice and mercy may be seen on all the earth." Welby then placed the St. Edward’s Crown on his head — with some effort! He spent a few moments making sure the crown fit comfortably on Charles' head.

The crown is nearly five lbs. of solid gold and features rubies, amethysts, sapphires, and more gemstones.

After the crowning of King Charles, Queen Camilla was crowned. After adjusting wisps of hair trapped by the heavy object, Camilla smiled and curtseyed before her husband.

The last time the U.K. witnessed a double coronation was 1936.

After the two were crowned, they disappeared from view and removed their crowns, returning for Holy Communion.

Still later, some two hours after the ceremony began, Charles wore the lighter Imperial State Crown for his procession back to Buckingham Palace in the Gold State Coach, which was built in 1760 and used by Queen Elizabeth at her coronation in 1953. The coach is notoriously uncomfortable and rarely used.

Once the King and Queen return to Buckingham Palace, Charles and Camilla are expected to make an appearance on the balcony with other senior royals.

Prince William is expected to take part in the special moment, while Harry will reportedly be leaving the festivities to return to California.