Paul Frecker has this biography of her with the next image: "Born Susannah Arethusa Cullum in 1814, she was the only child of Rev. Sir Thomas Gery Cullum, 8th Baronet, of Hardwick in Suffolk. In 1832 she married Thomas Milner-Gibson of Therberton House in Suffolk.
Her husband was originally elected to Parliament in 1832 as the Conservative member for Ipswich but resigned two years later, having adopted Liberal views. An ardent supporter of the free-trade movement, he became one of Richard Cobden's staunchest allies. In 1841 he was elected the MP for Manchester and although he lost his seat in 1857, he subsequently found another seat as the MP for Ashton-under-Lyne and sat in the Cabinet as President of the Board of Trade from 1859 to1866.
Milner-Gibson was the leading spirit in the movement for the repeal of taxes on knowledge, and his successful efforts on behalf of journalism and advertising were recognized by a public testimonial in 1862. He retired from political life in 1868, but he and his wife, whose salon was a great Liberal centre, were for many years very influential in society. Charles Dickens was only one of many distinguished members of their circle. Milner-Gibson was a sportsman and a typical man of the world, who enjoyed life and behaved liberally to those connected with him.
Thomas Milner-Gibson died on 25 February 1884. Mrs Milner-Gibson died almost exactly a year later on 23 February 1885 at 11, Bois de Boulogne, Paris. According to an announcement of her death in the Leeds Mercury (25 February 1885): 'The deceased lady was educated in a French convent, and spent many months every year in Paris, mixing a great deal in fashionable society.' According to the Pall Mall Gazette (25 February 1885): 'Mrs. Milner Gibson, who was a Roman Catholic, had for many years resided chiefly or wholly in Paris.' According to the Paris correspondent of the Manchester Times (28 February 1885): 'The death of Mrs. Milner Gibson, at the age of 71, will be much regretted by the leading English residents in Paris, who thus lose one of the few remaining attractions of Paris life. Daughter of the late Sir Thomas Gery Cullum, of Hardwick, Suffolk, and widow of the former President of the Board of Trade, Mrs. Milner Gibson had for many years resided chiefly or wholly in Paris, and her hospitality made up in part for the absence of other opportunities of social intercourse. She took much interest in spiritualism, and became a convert to Roman Catholicism. Paris is becoming less and less attractive as a place of residence to English people of fortune.'"