LONDON — Princes William and Harry put their differences aside on Saturday afternoon to pay tribute to their late grandmother, Queen Elizabeth II, and to greet members of the public outside Windsor Castle.

The princes were accompanied by their wives, the Duchess of Cambridge, now Princess of Wales, and Meghan Markle, Duchess of Sussex.

It was the first time in more than two years that the Duke and Duchess of Sussex were pictured with the Duke and Duchess of Cambridge. On Friday, Prince William and his wife were given their new titles by King Charles III: they are now known as the Prince and Princess of Wales.

The brothers and their wives came together at Windsor Castle to pay tribute to the queen, who died aged 96 on Thursday.

This is a moment that many have been waiting for: The brothers’ relationship has been strained following Prince Harry’s and Meghan’s exit from royal life and move to California, and since the couple publicly criticized members of the royal family in an interview with Oprah Winfrey last year.

The two couples took time to shake hands and speak with well-wishers outside Windsor Castle. They gazed at the notes and flowers left in memory of the queen, who was the country’s longest-reigning monarch, and who marked 70 years on the throne earlier this year.

Harry and Meghan arrived in the U.K. on Monday, where they attended the One Young World summit in Manchester, then flew to Dusseldorf, Germany, on Tuesday for the Invictus Games. Their short European tour ground to a halt following the queen’s death on Thursday.

At Balmoral, where the queen died, Princess Anne, Prince Edward and Prince Andrew greeted members of the public who were waiting outside the castle.

On Saturday afternoon the new Princess of Wales, and Meghan, both wore head-to-toe black as they emerged from the gates of Windsor Castle. Kate opted for a long-sleeved pencil dress paired with black tights and heels. Meghan wore a short-sleeved boat neck dress with matching black tights and shoes.

The last time the Sussexes were seen in public together with the Cambridges was on Commonwealth Day in 2020. At the time, Meghan wore an emerald green Emilia Wickstead dress, while Kate went for a deep red Catherine Walker number.

The family will be reunited again at the funeral of the queen at Westminster Abbey on Sept. 19.

Black has been the royal uniform of mourning for centuries. When Prince Albert died in 1861, Queen Victoria wore black until her death in 1901.

When Queen Elizabeth’s father King George VI died in 1952, she was on holiday in Kenya and immediately returned to the U.K., where she changed into a black dress as soon as she landed. Since then, it is protocol for royals to travel with a black outfit.

For the funeral of the Duke of Windsor in 1972, Wallis Simpson asked Hubert de Givenchy to make her a mourning outfit, and he stayed up all night to finish the job. Simpson wore a black veil with her black coat dress, while the queen and other members of the family wore black hats.