Diana came to prominence in February 1981 upon her engagement to Prince Charles, the eldest son of Queen Elizabeth II. Their wedding took place at St Paul's Cathedral on 29 July 1981 and made her Princess of Wales, Duchess of Cornwall, Duchess of Rothesay, and Countess of Chester. The marriage produced two sons, the princes William and Harry, who were then respectively second and third in the line of succession to the British throne. As Princess of Wales, Diana undertook royal duties on behalf of the Queen and represented her at functions overseas. She was celebrated for her charity work and for her support of the International Campaign to Ban Landmines. Diana was involved with dozens of charities including London's Great Ormond Street Hospital for children, of which she was president from 1989. She also raised awareness and advocated ways to help people affected with HIV/AIDS, cancer, and mental illness.