The eminent man whose biography this comes from is Cardinal Manning, but the man described here is the less eminent W.G. Ward.
The Sibyl being a prophetess.
This appears to have been written without the aid of any mind-altering substances at all.
Died in 1860.
Colette is the author of Gigi, made improbably into a musical featuring the song mentioned in the clue.
Chess players say "rook", not "castle", but never mind.
Written under the pseudonym "Acton Bell".
Oscar Wilde is supposed to have said that his wallpaper was killing him and one of them had to go.
Dante wrote (not here) in terza rima.
Kathleen Raine lost Gavin Maxwell's favourite otter.