Handel's opera Semele was first performed in 1744 as an oratorio, without set or costumes, and its success briefly lifted the composer out of an artistic rut. The libretto, adapted from Ovid's Metamorphoses by playwright William Congreve, concerns a Theban princess who falls in love with the god Jupiter. Juno, his jealous wife, disguises herself and persuades Semele to petition Jupiter for immortality, convincing her that to do so she must ask him to reveal himself in his godly form; when Jupiter grants Semele's wish, his heavenly radiance burns her to death. Though static and stylized in places--a shortcoming of Baroque operas in general--Semele has been held in high regard since its debut: it's full of verbal wit, delectable and elegant music, insightful character studies, and demanding arias (such as the tenor showstopper "Where'er you walk"). The Chicago Opera Theater, which has found a new lease on life by developing productions that take the starch out of the Baroque, is giving Semele a rare local revival as a fully staged opera. In his notes for this new production, British director Christopher Cowell talks about modern-day Semeles, drawing an analogy between the doomed heroine and women like Princess Di, who have "embraced then learned to fear the dazzling glare of celebrity and the fickleness of those who bestowed it." He seems likely to underline the humor in the story, as well as the feminist irony of Handel's moral lesson--that Juno, by using a decent woman's ambition against her, unwittingly does the dirty work for the dreaded patriarchy. Conductor Errol Girdlestone, a founding member of the Hilliard Ensemble, will lead a small orchestra that includes some of the city's finest early-music players; he's keenly aware of contrasting elements in Handel's music--restraint and humor, spirituality and bawdiness--and ought to be able to balance them all. The COT's youthful cast is headed by soprano Nathalie Paulin, the sensation from last season's Acis and Galatea, in the title role. Wednesday and Friday, May 8 and 10 (as well as Thursday and Saturday, May 16 and 18), 7:30 PM, and Sunday, May 12, 3 PM, Athenaeum Theatre, 2936 N. Southport; 312-704-8414.