Allen was a Guards officer in the Peninsular War, noted for his conduct at the battle of Talavera. He acquired the nickname "King" Allen.[2] He succeeded to the titles of 6th Viscount Allen, County Kildare, and 6th Baron Allen of Stillorgan, on 1 February 1816.[3]
Viscount Allen never married;[1] and on his death his titles became extinct.[4]
^Cokayne, George Edward (1910). The Complete Peerage of England, Scotland, Ireland, Great Britain, and the United Kingdom: Extant, Extinct, Or Dormant. Vol. I. St. Catherine Press, Limited. p. 111 note.