Lucia Mocenigo, heroine of this book, was a creature of flesh-and-blood reality, but her place is essentially in a novel. Among her immediate contemporaries, Stendhal could have worked this courageous and resourceful figure into La Chartreuse de Parme, and Goethe might have fashioned a new version of The Elective Affinities from her sentimental adventures as a married woman. There is a touch of Arnold Bennett’s The Old Wives’ Tale about her later years as a penny-pinching landlady on the Grand Canal, and a hint or two of Isak Dinesen in the final version of her, in rouge and false curls, offering iced lemonade to Effie Ruskin in the only heated salon of an otherwise freezing palazzo. By the time Lucia died in 1854, aged eighty-three, her life had become what sociologists like to call a paradigm, its variety of experience summarising a whole epoch of European history.

Her pedigree was Golden Book Venetian, as she was the daughter of Andrea Memmo, La Serenissima’s ambassador to the Papal States and descendant of one of the ancient republic’s first doges. Recently widowed when he arrived in Rome, Memmo was a wise father, anxious to secure good matches for Lucia