Allingham was a London solicitor. He was recorded as aged 36 in 1881, and was then living in Cricklewood, and was married to Georgiana. By 1891 they were living in Willesden and had two sons and three daughters. He was 56 when he died in 1901.
Allingham acted for both Whistler and C. A. Howell. He was involved in the affair of the Chinese cabinet in 1878-82; Whistler published his version of events in Correspondence. Paddon Papers. The Owl and the Cabinet, London, . On 30 June 1883, at an auction at Christie's, London, Allingham bought a 'Valparaiso' by Whistler, which could have been Symphony in Grey and Green: The Ocean y072 or The Morning after the Revolution, Valparaiso y075.
He lived at Hawthorn Lodge, Cricklewood, Edgware Road in 1881. His offices were at 55 Old Broad Street, E.C., between 1878-81.
UK census 1881.
Kelly's London Postal Directory, London, 1881; Whistler, James McNeill, Correspondence. Paddon Papers. The Owl and the Cabinet, London, ; Pennell, Elizabeth Robins, and Joseph Pennell, The Life of James McNeill Whistler, 2 vols, London and Philadelphia, 1908.
The Correspondence of James McNeill Whistler, 1855-1903, edited by Margaret F. MacDonald, Patricia de Montfort and Nigel Thorp.
'theodore frederwick [sic] allingham', Ancestry.co.