Princess Mary, Duchess of Gloucester and Edinburgh (d. 1857)
Princess Mary, Duchess of Gloucester and Edinburgh (25 April 1776 – 30 April 1857) was the eleventh child and fourth daughter of King George III of the United Kingdom and his consort Charlotte of Mecklenburg-Strelitz.
She married her first cousin, Prince William Frederick, Duke of Gloucester and Edinburgh, when both were 40, and was his widow in later life. In her last years, her niece Queen Victoria was on the throne as the fourth monarch during Mary's life, after her father and two of her brothers, George IV and William IV of the United Kingdom. Dying aged 81 at Gloucester House, Weymouth, Mary was the longest-lived and last survivor of George III's fifteen children (of whom thirteen lived to adulthood).