Arms: Quarterly 1st and 4th Argent a human heart Gules imperially crowned proper on a chief Azure three mullets of the field (for Douglas) 2nd & 3rd Azure a bend between six crosslets fitchy Or (for Earldom of Mar) all within a bordure Or charged with a double tressure flory-counter-flory Gules.
Crest: A human heart Gules ensigned with an imperial crown between two wings Or.
Supporters: On each side a Pegasus Argent winged maned and hoofed Or.
The Dukedom was created in 1708 in the Peerage of Great Britain for James Douglas (1672-1711), 2nd Duke of Queensberry (Peerage of Scotland). The Dukedom expired in 1788 on the death of the 2nd Duke, Charles Douglas (1698-1788) 3rd Duke of Queensberry.
Image courtesy of Richard Lichten