‘Farinelli and the King’ review: Wonderfully intriguing play

King Philip V of Spain is certifiable, of that there’s no doubt.

In Claire van Kampen’s wonderfully intriguing play “Farinelli and the King,” just opened on Broadway after two London runs in 2015, Mark Rylance all but devours the lush, candlelit scenery in his portrayal of the mad monarch, fully committed from the moment we first see him propped up in bed, fishing in a goldfish bowl.

Rylance is married to the playwright (known primarily as a music director, this is her first produced play) and while she has said the piece wasn’t written with her husband in mind, it’s hard to imagine anyone else in the role. Directed by John Dove, the triple Tony winner (“Twelfth Night,” “Jerusalem,” “Boeing-Boeing”) masterfully commands the mood swings of a manic-depressive, going from an introverted man hesitating over every word to a violent aggressor.

It is the court’s reaction to the king’s melancholy that drives the play, based, a program insert makes clear, on real events. The stand-by-your-man queen, Isabella Farnese (the charming Melody Grove) travels to London seeking the assistance of famed castrato Farinelli, having heard from the court doctor (Huss Garbiya) that music could potentially be calming.

Van Kampen has chosen dual casting for Farinelli: Actor Sam Crane portrays the right amount of conflict, speaking the part of the man who was born Carlos Broschi; countertenor Iestyn Davies beautifully sings the stunning arias in the difficult upper vocal ranges the style demands.

Oddly, the intervention appears to work, with the king improving, though increasingly reliant on the singer’s nightly concerts. But details are sketchy and questions arise, among them how Isabella ever convinced Farinelli to leave the stage (and the adoration of thousands) in the first place. And what of her role as the power behind the throne, which research (this show sent me straight to Google) suggests was extensive as the king became more indisposed? Or the hint van Kampen drops about a possible love interest between the queen and Farinelli? (Are you listening, Netflix? This little-known history could be a worthy successor to “The Crown.”)

Really, though, this is a play about the curative qualities of music. While it would be satisfying enough to simply embrace Rylance’s mastery and the glorious works of (mostly) Handel, there is a more significant message, one well documented by research but perhaps more valid to theater lovers in the soaring popularity of “You Will Be Found” from “Dear Evan Hansen.” Bullied, anxious, depressed? Music can make you feel better.