Born into a wealthy New York Loyalist family, originally French Huguenots from Caen, Colonel DeLancey was named after William Howe, Commander in Chief of the British forces in America, who resigned in the year DeLancey was born, and to some extent became a scapegoat for defeat.
After the War the Delancey family property was sequestrated, and most moved to Beverley in Yorkshire. William entered the army in 1892, obtained his commission at 15, and served with distinction during the Peninsular War. Throughout his military career he was known by colleagues as “The American”.
Colonel DeLancey was highly regarded by Wellington who refused to accept command in the Belgian campaign against Napoleon unless he could appoint him in place of Hudson Lowe, whom he disliked. Wellington's unwillingness to have Hudson Lowe was made clear by Major-General Sir H. Torrens in a letter to Earl Bathurst, the Secretary of War,
I shall communicate fully with the Commander-in-Chief upon the Duke of Wellington's wishes respecting his Staff ... As you were somewhat anxious about Sir Hudson Lowe, I must apprise you that he will not do for the Duke." (1)
DeLancey was duly appointed deputy quartermaster-general of the army in Belgium. Sir Hudson Lowe was offered command of the British troops in Genoa and then, whilst in the south of France in August 1815 was appointed to be Napoleon's gaoler on St Helena.
On meeting Sir Hudson Lowe for the first time Napoleon was horrified, and described his appointment as an insult. Maybe he was right!
DeLancey was seriously wounded at Waterloo whilst talking to Wellington. He was nursed by Magdalen, his bride of a few weeks, who was believed to be the inspiration for the character, “Lucy Ashton” in Sir Walter Scott's 1819 novel, The Bride of Lammermoor. He died of his wounds a little over a week later, a serious loss to His Majesty's service, and to me, said Wellington.
A few months later, shortly before embarking for St Helena, Sir Hudson Lowe married his widowed sister, Susan DeLancey Johnson. (2) Whilst on St Helena she became generally unpopular with all who come in contact with her, drank too much, made Sir Hudson's life a misery, and as was the lot of married women in those days, bore children at fairly regular intervals: Hudson (1816), Clara Maria Susanna (1818) and Edward William Howe de Lancey Lowe (1820). She died in Hertford Street, Mayfair, London, on 22 August 1832.
The Lowes' third child, Edward William Howe de Lancey Lowe, named after the uncle who had perished after Waterloo, was himself to have a distinguished military career. He married a daughter of Basil Jackson, who had been on Wellington's staff at Waterloo, had accompanied Hudson Lowe to St Helena, acted as his spy at Longwood, and in a combination of amatory and espionage pursuits had followed Albine de Montholon to Brussels when she left St Helena in 1819.
1. Major-General Sir H. Torrens to Earl Bathurst, Secretary for War, dated Ghent, 8th April 1815, quoted in introduction p. 11 to A Week at Waterloo in 1815, Lady De Lancey's Narrative , Edited by Major R.R. Ward, London 1906,
2. Lady Lowe's first husband, William Johnson had died in 1811. He too came from a New York loyalist family which had relocated to Canada. Lorenzo Sabine, Biographical Sketches of Loyalists of the American Revolution Volume 2, pp 574-582.