Lord Francis Douglas Marquess of Queensberry; a younger brother, Lord Archibald Edward Douglas (1850–1938), who became a clergyman; and a younger brother and sister, the twins Lord James Douglas (d. 1891) and Lady Florence Douglas (1855–1905), who married Sir Alexander Beaumont Churchill Dixie, 11th Baronet. He was an uncle of Oscar Wilde's lover Lord Alfred Douglas, and a younger brother of John Douglas, 9th Marquess of Queensberry. In 1858, Douglas's father, Lord Queensberry, died in what was reported as a shooting accident, but his death was widely believed to have been suicide. In 1862, his mother, Lady Queensberry, converted to Roman Catholicism and
Douglas of Mains – died ca. 1238), whose first son was William Longleg, Lord of Douglas and whose second son was Andrew Douglas of Hermiston. The title Laird of Mains was created in 1373, when Nicholas Douglas, son of the fourth Lord of Hermiston married Janet Galbraith, from whom he obtained the lands of Mains. However it was not until 1672 that the 11th Laird registered the coat of arms with the Lord Lyon King of Arms. Tracing the ownership of the title becomes increasingly difficult from the beginning of the 18th century, as the title became junior to the Campbells of Blythswood,