Family
Arnold married Mary Penrose, daughter of the Rev. John Penrose of Penryn, Cornwall. They had five daughters and five sons:
Jane Martha Arnold (1821–1899), married William Edward Forster
Matthew Arnold (1822–1888), poet and schools inspector
Thomas Arnold (1823–1900), literary scholar and Catholic convert
Mary Arnold (1825–1888), married (1) Alfred Twining, (2) Rev. John Simeon Hiley, (3) Rev. Robert Hayes
Rev. Edward Penrose Arnold (1826–1878), clergyman and schools inspector
William Delafield Arnold (1828–1859), author and colonial administrator
Susanna Elizabeth Lydia Arnold (1830–1911), married John Wakefield Cropper
Frances Trevenen Arnold (1832), died in infancy
Frances Bunsen Trevenen Whateley Arnold (1833–1923)
Walter Thomas Arnold (1835–1893)
W. E. Forster and Jane both enjoyed mountaineering; they climbed Mont Blanc in 1859 and in 1860 Jane was one of the first women to stand on the summit of Monte Rosa, which had not been climbed by a woman until 1857. When William Delafield Arnold died in 1859 leaving four orphans, the Forsters adopted them as their own, adding their name to the children's surname. One of them was Hugh Oakeley Arnold-Forster, a Liberal Unionist MP, who eventually became a member of Balfour's cabinet. Another was Florence Vere O'Brien, a diarist, philanthropist and craftswoman who lived in Ireland. Frances Bunsen Trevenen Whateley Arnold, the youngest daughter, never married and died at Fox How in 1923.
Arnold had bought the small estate of Fox How near Ambleside in the Lake District in 1832, and spent many holidays there. On Sunday, 12 June 1842, he died there suddenly of a heart attack "at the height of his powers", a day before his 47th birthday. He is buried in Rugby School chapel. Thomas the Younger's daughter Mary Augusta Arnold, became a well-known novelist under her married name, Mrs. Humphry Ward. His other daughter, Julia, married Leonard Huxley, the son of Thomas Huxley. Their sons were Julian and Aldous Huxley. Julia Arnold founded in 1902 Prior's Field School for girls in Godalming, Surrey.
