THEATER REVIEW:

South Coast Repertory has taken a few cracks at historical figures this season. “You, Nero” featured the incendiary Roman emperor and “My Mother’s Brief Affair” touched on executed spies Julius and Ethel Rosenberg.

Now it’s Emilie’s turn, Emilie being the brilliant 18th century French scientist La Marquise Du Châtelet (1706-1749), more remembered as Voltaire’s longtime mistress than for her own accomplishments. Playwright Lauren Gunderson has set out to level that playing field with her new project, “Emilie,” now receiving its world premiere on the Costa Mesa theater’s Julienne Argyros Stage.

Gunderson’s challenge is to take a period in history most playgoers probably know little about — the pre-French Revolution era known as the Enlightenment — and give it dramatic flight. This she and director David Emmes accomplish splendidly with the performance of Natacha Roi in the title role.

Roi assumes the persona of a dead Emilie, brought back to set the record — or at least her contribution to it — straight in an evening of entertainment subtitled “La Marquise Du Châtelet Defends Her Life at the Petit Théâtre at Cirey Tonight.” It’s not the only element of this play that’s a real mouthful.

Emilie’s fiery intellectualism, thwarted by a society which didn’t exactly take its women seriously, is seized upon with delicious vigor in Roi’s magnificent performance, particularly in her frequent faceoffs with Voltaire, interpreted with lusty intellect by Don Reilly. His character is the better-known figure in the play, but he’s clearly the second banana here.

Emilie, a prodigious scholar in science and mathematics, was overshadowed in life by Voltaire, the renowned writer and historian, and this slight is what she endeavors to correct in Gunderson’s play.

Their differences, particularly those involving the contributions to science of Sir Isaac Newton, propel a heated second act.

As a specter, however, she cannot come into physical contact with Voltaire or any other still-living person without short-circuiting the scene completely (an impressive technical achievement). This is where the stunning Soubrettte (Rebecca Mozo) comes in, pinch-hitting for Emilie in the play’s more intimate moments.

Matthew Humphreys fills several roles — Emilie’s husband, her late-life love — while Susan Denaker enacts older women in Emilie’s life. They along with Mozo are the show’s supernumeraries, adding required depth to the production.

Cameron Anderson’s bare stage setting ultimately takes shape as the centerpiece of Emilie’s appeal and the focal points of her life.

The costumes of Nephelie Andonyadis enrich the action markedly, while Lonnie Rafael Alcaraz contributes some shocking lighting effects.

“Emilie” may not be altogether accessible to audiences, bearing down as it does on 18th century principles of science and physics, but Roi’s performance as its heroine borders on brilliance.

IF YOU GO

WHAT: “Emilie — La Marquise Du Châtelet Defends Her Life at the Petit Théâtre at Cirey Tonight”

WHERE: South Coast Repertory, Julianne Argyros Stage, 655 Town Center Drive, Costa Mesa

WHEN: 7:45 p.m. Tuesdays through Fridays at 7:45 p.m., 2 and 7:45 p.m. Saturdays and Sundays at 2 and 7:45 p.m. until May 10

COST: $28 to $64

CALL: (714) 708-5555