Marianne Moore once famously defined poems as “imaginary gardens with real toads in them”. Operas also fill, or anyway should fill, their artificial horticulture with genuine beasts – and flowers. And no work demands the population of a fanciful landscape with authentic passion more urgently than Così fan tutte. Mozart transforms this shabby little shocker of a plot – as the meddling know-all Don Alfonso “tests” the two sisters’ fidelity to their sweethearts – into a vehicle for music of exquisite truthfulness that grows from a bed of fraud and lies.

We can’t do without Così fan tutte; it’s an irresistible masterpiece. But it’s a thorn in the flesh of modern directors, who struggle to find the "relevance" they seem to need in order to get the wretched piece on to the stage.

“Nobody likes a Messiah…”, deadpanned Robert Hollingworth, with the timing of a practised stand-up. After a pause, “…more than I do.” At St Martin-in-the-Fields on Friday evening, however, the seasonal blockbuster did not, just for once, feature on the festive menu. Instead, Hollingworth’s ever-enterprising ensemble I Fagiolini served up a savoury and well-spiced alternative to Handel’s ubiquitous staple.

“He’s my best friend, a brother,” says Felice Lasco (Pierfrancesco Favino) of his childhood buddy, Oreste Spasiano (Tomasso Ragno). After 40 years away, Felice, a successful, married businessman, has returned to Naples from Cairo to see his aged mother (Aurora Quattrocchi).

He hasn’t seen Oreste since he left at the age of 15. No letters, no phone calls. Nostalgia can be dangerous. A clue: Oreste is now known as Badman. Shades of Elena Ferrante’s Those Who Leave and Those Who Stay.

“It was the hand of God,” says the Neapolitan family patriarch about a rather unexpected consequence of Maradona's coming to play for the city’s team. That gives us a date, 1984, and, while the adolescent protagonist Fabietto remains in Naples, a fleeting sense of time and place.

The protagonist is a Neapolitan teenage girl; the settings move between the upper and lower parts, from the Vomero area on the hill to the industrial zone, of a city which has long been the main territory of the writer who calls herself Elena Ferrante. We know her through her “writer’s journey” Frantumaglia as irrefutably a woman from Naples - “an extension of the body,” as she describes it there, “a matrix of perception, the term of comparison of every experience”.

Roberto Saviano’s book Gomorrah shone a blinding light on the Camorra crime clans of Naples, and spun off an acclaimed film and equally admired TV series.

In her surprisingly self-revealing collection of essays and interviews Frantumaglia (Neapolitan dialect word for a disquieting jumble of ideas), the writer who calls herself Elena Ferrante often ponders the metamorphosis from novel to film.

It took no time for Elena Ferrante's two Neapolitan friends to join the ranks of great literary creations: Lenù as successful writer-narrator, critical of her past ambivalence; Lila the unknowable fascinator, her brilliance often diverted into poisoned channels. Four volumes amounting to over 1500 pages offer a psychological complexity four acts of fast-moving theatre can't begin to match.

This opening episode of My Brilliant Friend was a stunning symphony in grey.