The world's oldest and longest-serving monarch spent a night in the hospital on Wednesday but returned to Windsor Castle the next day, with officials stating she was feeling well and back to work. The queen had been advised by medical staff to rest for a few days, prompting her hospital visit, but her condition was not related to COVID-19. The palace confirmed on Thursday that she was in good spirits and back at work. Details on her medical issue were not disclosed, causing some to question if the full story was being shared. Prime Minister Boris Johnson sent his well wishes and noted that the queen had returned to her duties. Johnson informed reporters that Queen Elizabeth is back at work at her desk in Windsor, as per a royal source. The source explained that the queen had stayed at the King Edward VII hospital in London for practical reasons and her medical team had taken a cautious approach. Now, she is resting and performing light official duties. Despite being queen of 15 other realms, she returned to work on Thursday afternoon and is handling some light tasks. Elizabeth, who became queen during a time of significant change in Britain, has symbolized stability for generations of British people, helping to maintain the popularity of the monarchy. Her quiet and dedicated commitment to her duties, even in her old age, has earned her respect in Britain and around the world, even from those who want to abolish the monarchy. Elizabeth recently hosted a drinks reception for billionaire business leaders, including Bill Gates, at Windsor Castle, following a green investment conference organized by Prime Minister Boris Johnson before the COP26 climate summit. She was joined by her son, Prince Charles, and grandson, Prince William, as they greeted guests like US climate envoy John Kerry without wearing masks. The queen, dressed in a teal skirt and jacket with pearls, was photographed chatting and smiling with guests, including Johnson. Despite her advancing age, she remains in good health as she approaches her 70th year as queen. The last time she is believed to have stayed overnight in a hospital was in 2013 due to symptoms of gastroenteritis. In 2018, she had a successful surgery for an eye cataract and in 2003 for her knee. Royal officials typically avoid discussing her health issues. Her husband, Prince Philip, passed away in April at the age of 99, but she continues to fulfill her official duties, though she has delegated more tasks to Charles and other family members due to her age. Recently, she was seen using a walking stick in public for the first time, aside from after her knee surgery. She not only suffered the loss of her husband, whom she called her source of support, but also faced the resignation of her second son Prince Andrew from royal duties due to his association with Jeffrey Epstein, a convicted sex offender who died in jail in 2019. Additionally, her grandson Prince Harry and his wife Meghan have distanced themselves from the royal family and moved to Los Angeles, where they have criticized Buckingham Palace. Queen Elizabeth's upcoming significant event is at the end of the month when she will host world leaders at the opening of COP26 in Glasgow.