The sidelining of Anne will deprive the royal family of one of its most indomitable workers. She routinely logs more than 400 public events a year — often the most of any family member — and with the thinning of the ranks of senior royals in recent years, Anne has shouldered an even heavier load.

With the deaths of Queen Elizabeth II and her husband, Prince Philip, the illnesses of Charles and Catherine, and the departure of Prince Harry and his wife, Meghan, for the United States, the royal family has had a much smaller pool of members to pick up its busy calendar of royal duties and obligations.

After the queen’s death in September 2022, Anne, her only daughter, assumed unofficial status as the senior female figure in the House of Windsor, though in royal protocol she is outranked by Camilla, as the queen consort. Princess Charlotte, the 9-year-old daughter of Catherine and William, is the most senior female royal in terms of succession.

Like her brother Charles, Anne has weathered ups and downs in her personal life, as well as in her public image. As a young woman, she was sometimes viewed as haughty and sharp-tongued. But she became respected for her philanthropic work, serving as president of Save the Children from 1970 to 2017.

Anne’s first marriage to a fellow equestrian, Mark Phillips, ended in divorce, but she has had a stable second marriage to Timothy Laurence, a retired Royal Navy officer who served as an aide to the queen. An official said Mr. Laurence accompanied Anne to the hospital. He and her two children, Zara Tindall and Peter Phillips, were on the estate at the time of her accident, the official said.

In her public appearances, Anne is known for her brisk and unflappable demeanor — a characteristic she has displayed in other challenging episodes. In 1974, she survived a kidnapping attempt, telling the gunman who ordered her out of her car to hold her for ransom: “Not bloody likely!”