- King Charles III and Princess Anne are the eldest children of Queen Elizabeth II and Prince Philip.
- The siblings were born less than two years apart.
- Photos from their lives show how they spent time together as children and bonded as adults.
Their mother, then-Princess Elizabeth, was just two years away from her accession to the throne when Anne was born.
Charles, Anne, and the rest of the royal family spent a lot of time outside at their Scottish summer home.
The young siblings followed their parents and waved at the crowd from the balcony at Buckingham Palace after the Queen's coronation ceremony.
By the time their youngest brother Prince Edward was born in 1960, Anne was 13, and Charles was 15 years old.
Edward sat in Charles' lap as Anne rode her own go-kart around Windsor Castle.
The siblings also shared other hobbies when they were young. Anne and Charles enjoyed gardening as children, Woman and Home reports according to a 2004 interview Charles gave to BBC Radio 4.
"My sister and I had a little vegetable patch in the back of some border somewhere," he said. "We had great fun trying to grow tomatoes rather unsuccessfully and things like that."
Charles was made Prince of Wales, the title traditionally held by the heir to the British throne, in July 1958, Reuters previously reported. He was formally invested with the title at Caernarfon Castle in July 1969, with Anne accompanying him to the ceremony.
Video from The Royal Family Channel on YouTube shows archival footage of the siblings on safari at the Masai Game Reserve in Nairobi, Kenya's capital city.
In a photo from Anne's wedding to her first husband, Mark Phillips, Charles can be seen standing near his sister as she waved to the crowd from the Buckingham Palace balcony.
Anne was the first member of the royal family to compete at the Olympics when she rode her mother's horse, Goodwill, at the 1976 Montreal Olympic Games, according to the royal family's website.
Charles and Anne found a moment together at the Trooping the Colour Parade in 2000, which marked their mother's 74th birthday.
The siblings wore uniforms for the 2005 Order of the Garter ceremony. According to the website for the College of St George at Windsor Castle, both Anne and Charles are knights of the order.
The siblings found plenty to giggle at during the Braemar Highland Games, where athletes compete in traditional highland events, in 2009 and 2010.
Insider's Talia Lakritz's previously reported that despite some difficulties, Charles had a close relationship with his father.
Hello! Magazine writes that Anne also shared a tight bond with Philip. In a quote to the Daily Mail in 2017, Eileen Parker, the wife of Philip's friend Mike Parker, shared the differences between Charles and Anne by comparing them with their parents.
"[Philip] always had more fun with Anne," she said. "Charles is more like the Queen, while Anne is very like Prince Philip."
Photos of Prince Louis sitting with Charles and Anne bare a resemblance to images of the eldest siblings playing with their brothers.
Charles and Anne spent a lot of time in the spotlight after the Queen's death on September 8 at Balmoral. Hello! Magazine reports they were the first people at their mother's bedside when she fell ill because they were both already in Scotland.
At her funeral on September 19, the brother and sister, both in uniform, found time to talk alone. A source close to the king told Vanity Fair's Katie Nicholl that Charles "knows he has a loyal and faithful ally in the Princess Royal" and that he "absolutely plans to include her in his new streamlined monarchy."
Charles, Anne, and other senior members of the royal family gathered at the Cenotaph, a war memorial in London, England, for the annual event on Sunday. Anne was nearby when her brother laid a wreath to honor those who have died in world wars and other conflicts.