While continuing in business as a banker, Hodgkin devoted a good deal of time to historical study, and soon became a leading authority on the history of the early Middle Ages, his books. His magnum opus became Italy and her Invaders, published in eight volumes.
He died at Falmouth on 2 March 1913. His and the Hodgkin family papers are held at the Wellcome Library in London.
The family of Thomas and Lucy Hodgkin is listed as:
George (1880–1918) married Mary Wilson. Their son, Alan Hodgkin, received the 1963 Nobel Prize in Physiology.
Lucy Violet Hodgkin, later Holdsworth, was a writer and gave the 1919 Swarthmore Lecture under the title Silent Worship: The way of wonder.
She assembled her father's letters and wrote a memorial to her brother, George, published in 1923.
Ellen Sophia, later Bosanquet, wrote an autobiography, published by her daughter Diana Hardman, as Late Harvest: Memories, letters poems.
Hodgkin's chief works are:
Italy and her Invaders (8 vols., Oxford, 1880–1899; vols. I, II, 1890, (revised 1892), vols. III, IV, 1892 (rev 1896), vols. V, VI, 1895, vols. VII, VIII, 1899); republished as The Barbarian Invasions of the Roman Empire, (8 vols., The Folio Society, 2001) 
An introduction to the Letters of Cassiodorus: being a condensed translation of the Variae Epistolae of Magnus Aurelius Cassiodorus, Senator (London, 1886).
He also wrote a Life of Charles the Great (London, 1897); Life of George Fox (Boston, 1896); and the opening volume of Longman's Political History of England (London, 1906).
^Martin, G. H. (2004) "Hodgkin, Thomas (1831–1913), historian" in Oxford Dictionary of National Biography
^ abHodgkin, Thomas (2001). The Barbarian Invasions of the Roman Empire. The Folio Society. pp. General Introduction. ASIN B001UHAOK8.
^Hilton, Christopher (2004) "Hodgkin, John (1800–1875)" in Oxford Dictionary of National Biography
^ abcOne or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Hodgkin, Thomas". Encyclopædia Britannica. Vol. 13 (11th ed.). Cambridge University Press. p. 557.
^Quaker profiles by Sir George Newman, Bannisdale Press, 1946, pp.48-62
^Wellcome Library catalogue entry forn the Hodgkin Family papers. mundus.ac.uk
^Bosanquet, Ellen Sophie (1970) Late Harvest – Memories, Letters and Poems. p. 7.
^"Mr R. H. Hodgkin". Nature. 140 (3546): 676. 16 October 1937. Bibcode:1937Natur.140Q.676.. doi:10.1038/140676a0.
^George Lloyd Hodgkin 1880 - 1918 available online at Internet Archive