King Charles III gave his son William his old title, Prince of Wales, as he gave his first address as the new monarch on Friday evening. The 73-year-old became King following the death of his mother, Queen Elizabeth II, on Thursday at the age of 96. In his first televised speech as the King, Charles formally declared that his son and heir will now be known as the Prince of Wales, while William's wife Catherine will be the new Princess of Wales, a title formerly held by William's late mother Princess Diana.