[1] De Lancey sailed for Spain in 1835 with one of the first drafts from England, and on the way out showed his courage and presence of mind when his ship struck in a fog on the rocks off Ushant.
On landing he was placed at the head of a regiment of the legion, and, after serving as acting adjutant-general at the action of Hernani, accompanied Lieutenant-colonel Greville in command of the expedition to relieve Santander, which was then hard pressed by the Carlists.
The expedition was completely successful, and De Lancey received the cross of San Fernando and was appointed deputy adjutant-general to the legion.
[1] 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 government defences around the town, on 15 March 1837, which resulted in the rebel victory of Oriamendi.