Charles took part in 372 public engagements last year, even after stepping aside for almost three months because of cancer treatment, according to data compiled by The Times of London newspaper. That made him the second-busiest royal behind his sister, Princes Anne, who had 474 engagements.

King Charles was hospitalized briefly, more than a year after his cancer diagnosis, due to what Buckingham Palace called "temporary side effects" of his treatment.

Britain's King Charles has been seen in public for the first time on Friday, waving at well-wishers and passers-by after spending a short time under observation in hospital due to side effects related to his treatment for cancer.