Hepburn's mother, Baroness Ella van Heemstra (12 June 1900 – 26 August 1984), was a Dutch noblewoman. She was the daughter of Baron Aarnoud van Heemstra, who served as Mayor of Arnhem from 1910 to 1920 and as Governor of Dutch Suriname from 1921 to 1928, and Baroness Elbrig Willemine Henriette van Asbeck (1873–1939). At the age of nineteen, Ella had married Jonkheer Hendrik Gustaaf Adolf Quarles van Ufford, an oil executive based in Batavia, Dutch East Indies, where they subsequently lived. They had two sons, Jonkheer Arnoud Robert Alexander Quarles van Ufford (1920–1979) and Jonkheer Ian Edgar Bruce Quarles van Ufford (1924–2010), before divorcing in 1925.