 The expedition was completely successful, and De Lancey received the cross of San Fernando and was appointed deputy adjutant-general to the legion.De Lancey distinguished himself throughout the defence of San Sebastian, and especially in the action of 1 October, and was sent on a delicate mission to Madrid, which he carried out to the satisfaction of his general.Not long after his return to San Sebastian the Carlists made a determined attack upon the town, on 15 March 1837, and in repelling it De Lancey was killed at the head of his regiment, just as his more famous cousin, Sir William Howe De Lancey, Wellington's quartermaster-general, was fatally wounded at Waterloo.