Mary was educated by governesses, although she was allowed to share some lessons with her brothers and was particularly close to her eldest brother, Edward, who was known as David in the family. During the First World War, Mary accompanied her mother to hospitals and welfare organisations set up to ease the plight of soldiers and their families. In 1914, Princess Mary’s Christmas Gift Fund raised over £100,000 worth of gifts to be sent to soldiers and sailors. Mary developed a particular interest in the Girl Guides and nursing, eventually working in Great Ormond St Hospital in 1918 and becoming honorary president of the Girl Guides Association in 1920.
On 28 February 1922, Mary married Henry Charles George, Viscount Lascelles (1882–1947), the elder son of Henry Lascelles, 5th Earl of Harewood, and Lady Florence Bridgeman. The wedding, which took place at Westminster Abbey, was also the first royal occasion in which Lady Elizabeth Bowes-Lyon attended before marrying Mary’s second brother, Albert, who later became George VI.
There was a significant age gap between the bride and groom with Henry being fifteen years older and it was later suggested the marriage was arranged by Mary’s parents against her will. Apparently, Mary’s brother, David, to whom she was closest, was also against the marriage as he did not want his sister to marry a man she did not love. Later, Mary’s eldest son, George, refuted the claims, maintaining his parents had a lot in common and the marriage was a happy one.
Mary and Henry set up home in Goldsborough Hall in Yorkshire which Mary extensively modernised as a suitable home for her two sons and a railway station was opened nearby to make it easier for the King and Queen to visit their daughter. In 1929, Henry succeeded his father as 6th Earl of Harewood, Viscount Lascelles, and Baron Harewood, so the family moved to Harewood House where Mary found herself once again with a renovation project.
On 1 January 1932, George V bestowed Mary with the title of Princess Royal after the death of her aunt, Louise, Duchess of Fife. George V died in 1936 and was immediately succeeded by Mary’s favourite brother, David, who took the title Edward VIII, however his love for his American mistress would prove to be disastrous. Forced to choose between being king or being married to the woman he loved, he chose to abdicate and was exiled from the royal family. However, Mary remained close to David and stayed with him in Vienna after the abdication. She was also one of the few royals who ever met Wallis when the Duke and Duchess of Windsor travelled to London in 1965 so the duke could undergo eye surgery. A few days later, the duke was visited by his niece, Elizabeth II, who officially received the duchess.
A few days later, on 28 March 1965, Mary suffered a fatal heart attack while out walking with her eldest son on the grounds of Harewood House.