Catherine, Princess of Wales and Prince William attended the largest public gathering of royals since Andrew Mountbatten-Windsor‘s arrest.

On Monday (March 9), Kate Middleton and Prince William were among the guests at the annual Commonwealth Day service at Westminster Abbey in London. It’s also the same place where the couple were married in April 2011.

They were there to support King Charles and Queen Camilla. Princess Anne and her husband, Vice Admiral Sir Tim Laurence were also present, joined by the Duke and Duchess of Gloucester and Prince Albert of Monaco for the service.

There were other notable guests there, as well, such as former Spice Girl Geri Halliwell-Horner, a Royal Commonwealth Society Ambassador.

But the day also brought out anti-monarchy protestors, who were there with questions regarding the family’s handling of the former Prince Andrew‘s arrest.

According to ABC News, protestors were heard booing and chanting “Charles, what do you know?” as the guests arrived for the service.

Click through the gallery for more photos of Kate Middleton, Prince William, and the other royals at the Commonwealth Day service…