If only this delicate princess could connect in Sobler’s real-life historical fairy tale

Alix Sobler has form weaving drama from historical stories, breathing life into real characters and populating her worlds with believable fictional roles. In 2016 London played host to The Great Divide, her take on the 1911 fire in a New York garment factory that killed 146. The capital welcomes her back with the world premiere of The Glass Piano at the Coronet Theatre, fleshing out another true tale with her inimitable brand of metaphysical storytelling, laced with quirky humour.

In 19th-century Bavaria, eccentricity runs in the royal family. King Ludwig I has lost his queen – she's taken leave not of her senses, but of her royal spouse and duties. The lonely king takes to writing bad, self-regarding poetry and seeks affection from Galstina, the Bavarian maid left raising his daughter Alexandra. The princess herself believes that she swallowed a whole piano made of glass, so she moves with the greatest care, lest it shatter and destroy her with it. Remarkably, Princess Alexandra really did suffer from this delusion.

Though Galstina is Sobler’s own creation, the fourth member of her cast is also a historical character: Lucien Bonaparte, philologist, linguist and nephew of Napoleon. Sobler has him visiting Bavaria to study children "abandoned as babies and raised in the wild". Ludwig offers him hospitality in exchange for help with his poetry, but unsurprisingly he and Alexandra are drawn to each other (as they were in real life).

From these building blocks, Sobler constructs a drama as exquisitely eccentric and tragi-comical as her delicate princess. It's beautifully orchestrated by director Max Key and four actors who truly get to the heart of their characters. The quartet pace perfectly the fast, witty dialogue. The fifth member of the company is the superb pianist Elizabeth Rossiter, playing music specially composed by Gabriel Prokofiev, underscoring mood and character.

Grace Molony’s Alexandra appears so fragile in both mind and body that it seems entirely possible she will shatter if she makes a wrong move while negotiating the furniture in her gorgeous layered crinoline (elegantly designed by Deborah Andrews). She is heart-breaking in the self-imposed isolation this creates and it's a joy to see her moving towards real human connection as Laurence Ubong Williams’ smitten Lucien gains her trust – and she her confidence. At once gallant and nerdy, he hilariously professes his love in several of the 249 languages he speaks. Timothy Walker’s Ludwig is flamboyantly barmy and self-obsessed, clearly revelling in the dodgy couplets Sobler gifts him. It’s no wonder he adores down-to-earth Galstina, a touchstone for normality in this mad world in Suzan Sylvester’s wonderfully grounded portrayal.

The wood and red velvet of this former cinema is accentuated by Gothic interiors and a mirrored floor, courtesy of set and lighting designer Declan Randall. He achieves cinematic closeups with focused downlighting – supremely so in a romantic dance for both pairs of lovers. Go and discover whether or not the story has a shattering ending, and fall in love with Sobler’s wit and understanding of the frailties of the human condition.

By Judi Herman

Photos by Tristram Kenton

The Glass Piano runs until Saturday 25 May. 7.30pm. £25-£30, £20-£25 concs. Print Room at the Coronet, W11 3LB. 020 3642 6606. www.the-print-room.org