The rose window at St. John the Divine in New York.

One of the great achievements of the early music movement - and Martin Pearlman's Boston Baroque in particular - has been its reclamation of Monteverdi from his lapsarian status as "that Italian guy before Bach." Last weekend's performances of the great composer's Vespers of 1610 only cemented that achievement. Monteverdi should have always been set somewhere on the boundary of Big Three territory, in that he brought pre-baroque forms such as the madrigal to the highest pitch they ever reached. But as early music pioneers have made us more and more familiar with his masterpieces, his status as a forger of new musical form has begun to seem to rival Beethoven's and Wagner's. Monteverdi of course all but invented opera, but nearly as original is his Vespers, a work unprecedented (at the time) in its scope and ambition, and one that all but defies categorization even today.

Of course on the surface, Monteverdi pretty much follows the normal structure of the Catholic rite of vespers, the evening ritual in which a series of sung psalms and antiphons leads to a Magnificat, a canticle dedicated to both the glory and humility of the Virgin Mary. In fact the Vespers was written, many believe, as a kind of audition for the top musical post at St. Mark's cathedral in Venice (Monteverdi got the job).

But it's hard to look at this piece as a résumé-builder, even for a genius; instead it sometimes feels like a kind of musical big bang, a technical, stylistic, and metaphorical explosion that in a way kick-started everything. Monteverdi leaps from motet to sonata to psalm and back again, all while somehow maintaining a sense of unity; he splits and re-forms his choir at will, and sometimes provides them with up to 10 separate vocal parts, all operating in synchrony(the piece also calls for seven soloists). What's more, Vespers is set all over the performance space, be it cathedral, chapel or concert hall - sometimes we can't even see the singers, as they're intended as voices of the cosmos, responding re-assuringly to the profession of human faith.

Now I don't believe in God, but Monteverdi certainly did (he eventually became a priest), and frankly, sometimes he almost convinces me of His existence. There are few more haunting moments in all of Western music, for instance, than "Duo seraphim," his duet for two angels floating in space, singing the glory of the Almighty (they're eventually joined by a third, who fuses with them into a single note when they praise the Trinity). Here conductor Martin Pearlman placed his tenors, Derek Chester and Aaron Sheehan, in the balconies of Jordan Hall, to thrillingly plaintive effect, and Monteverdi's evocation of the mystery of God's presence gripped us not only as great music but also as great theatre (and maybe even great architecture).

Alas, not all the soloists fared as well from the stage itself. Mr. Pearlman had clearly instructed his singers to strip their styles down toward pure-tone singing, and so I missed some of the vocal richness I expected from Mary Wilson and Kristen Watson, who both shone to better advantage in operatic roles with Boston Baroque earlier this year; indeed, of Pearlman's soloists (almost all of them familiar from earlier programs) I felt only baritone Donald Wilkinson was operating at his best. And the wind section, though fine in unison, sometimes got a little ragged when each instrument was exposed for long stretches. Likewise the height of Monteverdi's polyphony - those 10-part-plus sequences - didn't always feel entirely coherent.

But this is, admittedly, an incredible challenge, and any roughness here may have been partly due to understandable opening-night coordination issues; at any rate the chorus generally sounded superb, and nowhere more beautiful than in Monteverdi's concluding Magnificat, one of the most touching ever written. And Pearlman's mastery of the total arc of the Vespers was always and everywhere evident. The piece calls for a high degree of editorial intervention; much of the instrumentation is suggested but not pinned down, the position of some motets is disputed, and precisely which antiphons should be included is never specified (Pearlman took his from the Feast of the Assumption, certainly an appropriate choice). It's no secret that Pearlman's decisions on these and other key points have led to a version that many consider "the" Vespers of our time (it's already won a Grammy). Certainly the "Pearlman version" limns every - sometimes contradictory - facet of the piece: its intimacy and its grandeur, its period "feel" and yet its strange sense of timelessness. His exploitation of every nook and cranny of Jordan Hall was also brilliant, and only makes me long to hear this version in New York on March 6, when Boston Baroque will bring the Vespers to the Cathedral of St. John the Divine, surely a close-to-ideal venue for hearing Monteverdi's music of the spheres.

The triumph of "Love"

I simply don't have time this morning for a full review of Handel and Haydn's "Zest for Love" program, which repeats on Sunday, but I felt I had to write a few lines to try to persuade anyone who might be on the fence, or who hasn't yet thought of this as a potential Valentine's Day treat, to by all means go. The concert is another musical "salon" from this always-experimenting company, though not everything in it is strictly musical: there are also spoken texts, all from Shakespeare, delivered by actors from the Huntington Theatre. The musical program, assembled by conductor Laurence Cummings, is mostly madrigals (and mostly Monteverdi, with Shakespeare at left), but also features two wonderful instrumental obscurities: a passionate Quarta sonata from Dario Castello - marked by fierce bowing from violinists Christina Day Martinson and Susanna Ogata - and an absolutely gorgeous Ciaconna from Tarquino Merula. The Shakespeare readings, subtly directed by Peter DuBois in an unexpected fit of maturity, were often superb - actor Lee Aaron Rosen in particular impressed (even more than he did in All My Sons); this performer could have great Shakespeare in him, given the chance. The H&H singers, particularly Teresa Wakim and Lydia Brotherton, were in fine form, and while diction was at times a bit blurry, the musical balance was usually exquisite. Perhaps most importantly, the evening's theme - "love," of course - was hardly given the swoony treatment one might expect on Valentine's Day; indeed, this counts as one of the deepest statements on that hallowed emotion I've heard in some time. The juxtaposition of Shakespeare's verse and Monteverdi's madrigals even opened a new window for me onto the Bard - but more on that later. For right now, just go. Tickets for the Sunday afternoon performance at Sanders Theatre are available here.

Crowning achievement

Every ill wind, as the saying goes, blows someone some good, and ironically enough our current economic downdraft has wafted an operatic masterpiece our way: the Boston Early Music Festival, which generally devotes itself to extravagant obscura (which once or twice has turned out to be deservedly obscure) was forced by financial concerns to cancel Christoph Graupner's Antiochus und Stratonica and substitute Monteverdi's smaller-scaled, better-known masterpiece, L'incoronazione di Poppea (with Gillian Keith and Marcus Ullmann, above left).

And with all due respect to Christoph Graupner (who knows, perhaps Antiochus and Stratonica is brilliant!) I have to say: lucky us. For Poppea has remained in the repertory for nearly four hundred years for a very good reason: it is simultaneously ravishing, heart-breaking, and startlingly profound, an amalgam of the warmest romance and the coldest irony that keeps us constantly on our emotional and intellectual toes. And while it's hardly unknown to the opera buff, it's rarely been seen in these parts - and, I'd hazard, rarely seen anywhere to better advantage. For not just the economic stars have aligned for this production: its setting, the Wimberley Theatre at the BCA, turns out to be a superbly intimate venue for chamber opera, and BEMF has assembled one of the best casts - in dramatic as well as vocal terms - in its history. In short, L'incoronazione di Poppea is good enough to make you feel that the downturn in your 401(k) may just have been worth it.

Still, marvelous as it is, this Poppea's not perfect. Specialists could disagree with some of the instrumental and vocal decisions made here (any performance must be "reconstructed" from two varying versions), but I've got no dog in any of those possible fights. There's a slight, but understandable, fudge to the tone of Gilbert Blin's direction, however, and there are vocal and/or dramatic gaps in the two leads (it's the supporting cast that pushes the opera well over the top). In the case of the direction, it must be said that the tone of this libretto (by Giovanni Francesco Busenello) is among the subtlest challenges in opera, and one that puts to shame the seemingly tinny ironies of most modernist and postmodernist works. The piece centers on the Roman emperor Nero and his consort Poppea, whom he eventually crowns as empress, after disposing of his understandably-scheming queen Ottavia (banishment), the protesting philosopher Seneca (death), and Poppea's own husband Ottone (again banishment, but this time with the loyal Drusilla by his side, whom he slowly learns to deserve). But Poppea's day in the sun didn't last long: once pregnant, she was kicked to death by her unstable hubby. So "The Triumph of Love" this ain't.

Oh, but it is. Perhaps only Vladimir Nabokov has pulled off the kind of trick that Monteverdi and Busenello manage with L'incoronazione di Poppea: an ode to love which simultaneously seduces and sobers - even horrifies. The opera begins with a standard-issue quarrel among the gods (here Virtue, Fortune, and Love) over who has the most power over life on Earth. Love claims precedence, of course, and then sets about proving her dominion via the elevation of the lovely Poppea against all arguments of reason, political justice or morality. But hey, that's amore! That Poppea is wedding a budding sociopath, and that her ascension will wreak havoc on the state (Seneca prepares for his "suicide," at right), are but trifles before the power of sexual attraction.

What proves most haunting about Poppea, however, is that throughout this ongoing moral and political travesty Monteverdi manages to keep some level of sympathy with everyone (even Nero). Because all the characters are at some level a victim of emotional or political forces beyond their control. (Even Poppea is the plaything of her own beauty.) But this perspective requires, at bottom, a certain chill in a production's conception of Love - the godlet can't be merely some mischievous putti, but requires at least the alien distance of Shakespeare's Ariel, and perhaps even the terrifying calm of Apollo while flaying Marsyas. Director Blin, however, keeps soprano Nell Snaidas's Amore well within a certain winking cuteness, which is fine at first but begins to feel inadequate to the eventual size of the opera's moral debate. To be fair, the director does work Virtue and Fortune back into the action at appropriate moments, but then he seems to drop the ball again with Nero and Poppea, whose relationship isn't nearly glamorously twisted enough - although one could argue that the central gap here is simply Marcus Ullmann's Nero. Ullmann was re-purposed from the cast of Antiochus und Stratonica, and he's none too comfortable with the upper vocal reaches of his new role (which was originally written for a soprano), and perhaps that's hampering him dramatically. But at the same time he is simply neither a complex nor powerful enough presence to anchor the opera - which leads to an implicit presentation of Poppea (Gillian Keith) as a gold-digger, another slight error in interpretation. But if Keith doesn't quite limn the fearful uncertainty of her political position, she nonetheless sings the role ravishingly, with a honeyed soprano that is simultaneously light, rich, and luminously subtle.

And the vocal riches just keep on coming, generally combined with pitch-perfect dramatic characterizations. Stephanie Houtzeel all but steals the show as the spurned Ottavia, with a vocal power and a tragic hauteur that would have filled a much larger house. She was nearly matched in stature, however, by Christian Immler's Seneca - Immler deployed his deeply vibrant voice to poignant effect, while holding back dramatically from any overt melodrama; thus his preparation for his suicidal bath was probably the most heart-rending scene on a local stage in recent memory.

The list of wonderful performances in this production is long, however. Amanda Forsythe made an emotionally compelling and vocally radiant Drusilla, while as her eventual mate Ottone, Holger Falk negotiated many an emotional twist without missing a beat, all while sporting an agile and rich baritone (although he too was occasionally stretched in his upper register). Another scene-stealer was Laura Pudwell as Poppea's nurse (above) - an earthy busybody straight out of Shakespeare. I was also taken with Deborah Rentz-Moore's Virtue, Ross Hauck's Lucano, and Jesse Blumberg's Mercurio. And all received truly dazzling accompaniment from the period orchestra, which featured particularly sparkling work from Paul O'Dette and Stephen Stubbs on Baroque guitar and theorbo (those giraffe-like period banjos), Luca Guglielmi and Jörg Jacobi on harpsichord, and Maxine Eilander on Baroque harp. It was hard not to feel as the curtain fell (to rapturous applause), that L'incoronazione di Poppea would prove the cultural event of the summer, and perhaps the Boston Early Music Festival's crowning achievement.