Princess_Mary,_Duchess_of_Gloucester_and_Edinburgh--Princess_Louise,_Duchess_of_Argyll

Princess Mary, Duchess of Gloucester and Edinburgh (25 April 1776 – 30 April 1857) was the eleventh child and fourth daughter of King George III 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. Dying aged 81 at Gloucester House, Weymouth, Mary was the longest-lived and last survivor of George III's fifteen children (thirteen of whom lived to adulthood).