Thomas Weldon Trench was born in 1833, the son of William Steuart Trench (1808-1872) of Cardtown, Queens County, Ireland, a landowner and land-agent, and Elizabeth Susan Trench (d.1886), née Townsend. (Also born to the marriage were John Townsend Trench (b.c.1834) and Anna Maria Bolero (1836-1903), née Trench.) He served as a humanitarian volunteer during the Franco-Prussian War, arriving in the war zone in September 1870 and returning in late October following an attack of dysentery. Dr. Christopher James Davis (1842-1870), originally from Barbados, was a house physician of St. Bartholomew's Hospital, London; he died of smallpox in November 1870. British humanitarian efforts during the War were initiated by Colonel Robert Loyd Lindsay (1832-1901), later Baron Wantage, a veteran of the Crimean War and associate of Florence Nightingale.