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
William I, Lord of Douglas Meic Uilleim chief. This may be corroborated by the facts that the lands of Douglas marched with those of the leader of King William I of Scotland's retaliatory forces, Lochlann, Lord of Galloway. William may well have been a vassal of the Lord of Galloway. Furthermore, all of William's sons with the exception of the eldest were to hold privileged ecclesiastic positions within the former Meic Uilleim territories in Moray. William of Douglas may have married Margaret, a sister of Freskin of Kerdal, a Flemish laird from Moray. He had issue: William I, Lord of Douglas William of Douglas (died