The Prince of Wales has been the traditional title for the male heir to the throne since around 1301, and William's wife Kate became the Princess of Wales in the same sweep, taking on the title her late mother-in-law, Princess Diana, was popularly known by during her marriage to Charles.

Kate, the Princess of Wales, marked another milestone in her return to public duties after announcing her cancer diagnosis, delivering her first public speech in over two years. Kate delivered a speech Tuesday on a topic close to her heart, early childhood.