Mark Rylance and Melody Grove sparkle as the royal couple in this story of the curative power of music. Farinelli and the King is a historical drama, housed at the Sam Wanamaker Playhouse where candlelight waxes lyrical on a dark wood and gold set. Rich, gorgeous costumes romance the stage and baroque arias sweeten the story in interludes of musical performance; but there is nothing cloying about this sharp and witty play.

Knowingly contemporary language breaks into the archaisms (everyone swears a lot) and Rylance swings between comic innocence and angry depression as King Philippe V. It begins in dreams and whimsy with childlike storytelling: Rylance is fishing in a goldfish bowl, whiling away his withdrawal from life and kingship with idle play. Chattering away to the little fish, he is endearing, amusing, clipped, reticent and yet very sure – teetering towards dangerous.

His wife Isabella (Grove), beautifully costumed in an elaborate lavender dress and bright jewels, is the key to his healing. Grove dazzles in the role with wide eyes and a firm handling of the king’s dreams and absurd whims. Under recommendation from her husband’s doctor, she boldly travels back to her Italian homeland to attract the renowned castrato singer Farinelli (Sam Crane) to come to the Spanish court. As the singer himself pronounces in a game of truth telling the king constructs: it is Farinelli who is famous, not he himself.

There is the sense throughout this domestic and intimate look into kingship and stardom that healing is in quiet and art and song. It contrasts firmly with the brash and unfeeling orders of the Chief Minister of Spain, De La Cuadra (Edward Peel), whose disloyalty and arrogance impede the king’s retreat into music. It makes the king’s recovery all the more triumphant.

The librettist Metastasio, played by Colin Hurley, takes a similar managerial role over the elusive and flighty Farinelli. Why would a world-renowned singer shun the world and the opera houses to stay and sing for an ill-disposed and difficult king? The young singer finds freedom for his voice away from the thorns and overwhelming scent of the roses that in public performance fall at his feet. Both Farinelli – mutilated when he was ten to become a king of song – and Philippe – a kingly outsider on the Spanish throne – struggle with their responsibilities and fame. Outside of the court, in a pastoral repose of music and gardens, healing is found.

Dualisms and parallels like these abound in the play: court and country, peace and pain, violence and love, truth and dreams. It’s quite Shakespearean really in its themes. There’s no surprise there, given its setting at the Sam Wanamaker Playhouse and that the playwright (Claire van Kampen) spent ten years as musical director of the Globe, at the time that her husband Rylance was artistic director. She wrote the play unambiguously with Rylance in mind for the part of the king, inspired by his handling of the maddened but sympathetic Hamlet in 1988 and 2000. The most featherweight of lines lies between Rylance and Philippe, so wholly does the play construct the part around his idiosyncrasies.

Characterisation aside, van Kampen’s skill comes into its own in her deft weaving together of text and song – it is a self-professed “play with music”. Her understanding of musical language forms this, her first play, into something of contrapuntal beauty. Farinelli is played by two performers, one to act him and the another to sing. It works and it feels necessary, although the counter tenor’s handling of the legato line in the arias is brilliant but not always perfect.

This play is a timely call for patronage of the arts and their necessity for the health of individuals and our nation, as insensitive funding cuts have driven arts companies and organisations into being evermore entrepreneurial. Most of all, it is testament to the solace of art and its soothing power over the mind.

Farinelli and the King is playing at the Sam Wanamaker Playhouse until 8 March. For more information and tickets, see the Shakespeare’s Globe website. Photo by Marc Brenner.