Biography
Daughter of Windmill Crompton, a London linen-draper. Married (1748) to Hugh Hume-Campbell, 3rd Earl of Marchmont with whom she had one son, Alexander (1750-1781).1
Sir James Balfour Paul wrote that "[a]t the time of her marriage in 1748 she was only about seventeen, and the Earl was so infatuated with her that he proposed to her the day after seeing her for the first time in a box at the theatre. She was painted by Reynolds, and an old retainer described her as 'just the fairest creature that ever stept this earth'"
2
Life with Boswell
Boswell met Lady Marchmont at Marchmont House on October 18, 1762. He described her as "a sweet-looking agreeable woman[, who] was a citizen's daughter and brought him money."