Rosita Spencer-Churchill, Duchess of Marlborough

Dagmar Rosita Astrid Libertas, Duchess of Marlborough (née Douglas, sometimes Spencer-Churchill; born 26 September 1943, Madrid) is a British artist of Swedish and German descent. She was the third wife of John Spencer-Churchill, 11th Duke of Marlborough, from 1972 until their divorce in 2008.

She was born as Countess Rosita Douglas in Madrid, Spain, the younger daughter of Count Carl Ludvig Douglas (1908-1961), a Swedish nobleman and diplomat who was Royal Swedish Ambassador to Brazil and his Prussian wife Ottora Maria Haas-Heye (1910-2001), maternal granddaughter of Prince Philip, 1st Prince of Eulenburg and Hertefeld, by his wife Augusta, Countess Sandels. She grew up as a diplomat’s child, travelling all over the world but spent her summers at the family home, the castle of Stjärnorp, which belonged to Rosita's paternal grandfather, General Archibald Douglas.

Rosita Douglas attended schools in Sweden and in Washington DC. She studied arts at Sweden’s renowned art school Konstfack in Stockholm, and then at the École nationale supérieure des arts décoratifs in Paris. While in Paris she also worked for the famed fashion designer, Emanuel Ungaro and later as a freelance designer in London.

On 20 May 1972, Rosita Douglas became the third wife of John Spencer-Churchill, 11th Duke of Marlborough, an Englishman who had inherited his father's estates and titles two months before. She thus became Duchess of Marlborough, with a number of residences which included Blenheim Palace in Oxfordshire. They had three children:

1. Lord Richard Spencer-Churchill (born 1973; died four months later as an infant)
2. Lord Edward Albert Charles Spencer-Churchill (born 1974),
3. Lady Alexandra Elizabeth Spencer-Churchill (born 1977).

The Duke and Duchess were divorced in 2008, after several years of living separately.According to newspaper reports, the Duchess moved into a smaller house on the Blenheim estate and also bought herself a house in France.

In 1992, the duchess returned to art as a professional. She has had two solo exhibitions in London and one in Palm Beach. Her first show in London in 1995 featured figurative paintings. Since then, she traveled to Morocco in 1996, and her paintings of Moroccan themes sold briskly.She has since exhibited and sold paintings inLondon, New York, and Palm Beach. Her paintings and sculptures are in collections around the world.She has also had a retrospective Rosita Marlborough: A Retrospective at the Elizabeth de C. Wilson Museum at the Southern Vermont Arts Center from July 15-September 1, 2006.

Rosita Marlborough is a maternal aunt and godmother of Princess Sophie, The Hereditary Princess of Liechtenstein and maternal aunt of her sisters, Duchess Marie-Caroline, Duchess Helene, Duchess Elisabeth and Duchess Maria-Anna, who are all Princesses of Bavaria. Her elder sister Princess Elisabeth (b. 1940) is married to Prince Max, Duke in Bavaria, heir presumptive to the Headship of the Royal House of Bavaria and also heir presumptive to the Jacobite pretensions to the thrones of England, Scotland, Ireland, and France. Her elder brother is Swedish businessman Count Gustaf Douglas.

Her maternal aunt was Libertas Schulze-Boysen née Haas-Heye (1913–1942), who with her husband, Harro Schulze-Boysen (1909–1942), were executed by the Nazis. Her maternal great-grandfather was Prince Philipp, 1st Prince of Eulenburg and Hertefeld (a best friend of Emperor Wilhelm II of Germany), whose youngest child Princess Viktoria Ada Astrid Agnes of Eulenburg and Hertefeld (1886–1967) married 1909 (divorced in 1921) professor Otto Ludwig Haas-Heye (1879–1959) and had issue, including two daughters. Rosita descends through both her mother and father from medieval Scandinavian nobility and rulers. However, her father's patriline is Scottish, of the Swedish-German branch, descended via two obscure generations, descended from the youngest son of James Douglas, 1st Baron of Dalkeith, ancestor of the 15th century Earls of Morton. All these Douglases were of the Morton branch of the ancient Douglas family.

• 1943–1972: Countess Dagmar Rosita Astrid Libertas Douglas-Stjernorp auf Mühlhausen und Langenstein
• 1972–2008: Her Grace The Duchess of Marlborough
• 2008–present: Rosita, Duchess of Marlborough