p 70 | ..."the supple form of a winged victory." Whist card game.
p 71 | ... "Harmony in Black and White" by Whistler ; Maltese cross
p 72 | ... "tilting at windmills"= attacking imaginary enemies
p 73 | Nuncio (also papal nuncio)= an ecclesiastical diplomat (like an ambassador), a representative of the Holy See to a state; usually an archbishop. Duc d'Aiguillon (but which one?)
p 76 | Hubert Robert (1733-1808), French painter of ruins & views & landscapes & fountains. See some works here, a bit of erotic symbolism here
p 77 | Grand Duke Vladimir Alexandrovich of Russia (1847–1909), the second son of Tsar Alexander II; he spent long periods in Paris with his wife, Maria Pavlovna, who appears in the final volume of the novel (Sturrock notes).