Margaret of Prussia was the youngest child of Frederick III, German Emperor, and Victoria, Princess Royal. She was also the younger sister of Emperor Wilhelm II and the granddaughter of Queen Victoria. She married Prince Frederick Charles of Hesse, the elected King of Finland, making her the would-be Queen of Finland had he not decided to renounce the throne on 14 December 1918. In 1926, they assumed the titles of Landgrave and Landgravine of Hesse. The couple had six sons and lost three of them in wartime, two during the First and one during the Second World War.

Frederick III was German Emperor and King of Prussia for 99 days between March and June 1888, during the Year of the Three Emperors. Known informally as "Fritz", he was the only son of Emperor Wilhelm I and was raised in his family's tradition of military service. Following the unification of Germany in 1871 his father, then King of Prussia, became German Emperor. Upon Wilhelm's death at the age of ninety on 9 March 1888, the thrones passed to Frederick, who had been German Crown Prince for seventeen years and Crown Prince of Prussia for twenty-seven years. Frederick was suffering from cancer of the larynx when he died, aged fifty-six, following unsuccessful medical treatments for his condition.