It's a funny thing about "Golden Ages": they are almost always behind us, and are often only recognized in retrospect. But for all you opera aficionados out there who worry that the heyday of the heldentenor or Verdi soprano has passed you by, take heart: You are currently living in an operatic Golden Age‹the Golden Age of the Countertenor.

While a vocal rarity only 20 years ago, countertenors are currently everywhere. They're winning major vocal competitions, performing music that ranges from baroque to minimalism, and are being featured in mainstream media outlets such as Vanity Fair and 60 Minutes. This month at the Met, the company premiere of Handel's Rodelinda features two of the world's better known exponents: David Daniels and Bejun Mehta.

What makes this particular Golden Age even more exciting is the fact that it is without historical precedent. For, like many aspects of the "early music" movement, the countertenor voice is largely a 20th-century invention. In fact, countertenors didn't even exist in the world of opera until 1960.

The term, however, had actually been around for centuries before this. In medieval church music, it indicated a voice part written "against" the tenor, or main, vocal line, and included both high (contratenor altis) and low (contratenor bassus) voices. Over the later medieval, renaissance, and baroque periods these labels evolved, with "contratenor altis" becoming "countertenor" in England, "hautecontre" in France, and "altist" in Italy.

In the 17th century, British composer Henry Purcell, who is thought to have been a countertenor himself, wrote music for English countertenors that wanted to imitate the then-popular Italian castrati‹men who were castrated as boys to preserve their high singing voices, since the Catholic Church banned women from singing on the stage or in the church. But as musical tastes changed and social structures reformed, castrati became less and less popular. By the nineteenth century, these former stars of the opera stage had been forsaken; and the baroque vocal works in which they were featured, like Handel's operas, fell by the wayside. During this time, the countertenor voice, secularly speaking, disappeared as well‹though it continued to lead a somewhat shadowy existence in church choirs under the designation of "male alto."

It was just such a church alto, the British singer Alfred Deller, who brought the countertenor voice into the classical concert hall after centuries of cloistering. Deller was singing in the choir of St. Paul's Cathedral in London when he was discovered in 1944 by the composer Sir Michael Tippett, who, upon hearing him, declared, "in that moment, the centuries rolled back." Tippett helped to launch Deller as a concert artist, and, upon his advice, Deller revived the term "countertenor" to describe his unusual, high-pitched singing style. In 1948, Deller, at the forefront of the early music movement, founded the Deller Consort, a vocal ensemble specializing in medieval, renaissance, and baroque music.

Tippett wasn't the only composer intrigued by Deller's otherworldly sound. In 1960 British opera composer Benjamin Britten wrote the role of Oberon in his opera A Midsummer Night's Dream as a vehicle for Deller, and, in doing so, created the first role in a fully staged opera specifically for the countertenor voice. Deller debuted the part of Shakespeare's famous fairy king at the Aldeburgh Festival that same year, and made musical history in the process.

Yet, unlike the majority of contemporary countertenors, who use their entire vocal chords to produce a sound that is rich and resonant, Deller was a falsettist, using only the edges of the vocal chords to create a thinner, lighter voice that was better suited to songs, oratorios, and chamber opera than larger operatic works. (Think Aretha Franklin vs. Smokey Robinson, and you've got the general idea.) American countertenor Russell Oberlin, who followed closely on Deller's heels and took over the role of Oberon when Britten's opera premiered at Covent Garden, claimed to be a "true countertenor" because, according to him, he didn't use any falsetto. Even so, Oberlin's voice, like Deller's, was comparatively light‹and he also retired from singing in 1964, at age 36, which did little to further the countertenor's cause.

So, while the early music movement was giving new life to forgotten baroque operas, the countertenor voice, thought not to be large enough to tackle Handel's heroic leads in the world's major opera houses, remained an operatic oddity. Roles once sung by castrati were instead transposed for tenor, or even bass‹such as in the premiere of Handel's Giulio Cesare at New York City Opera in 1966, which starred bass Norman Treigle in the title role. Mezzo-sopranos such as Marilyn Horne and Janet Baker proved more successful in reintroducing these long-neglected works to modern audiences; but, although accepted in traditional trouser roles, mezzos were admittedly less convincing as conquerors and kings.

The appearance of James Bowman, another British "cathedral countertenor," in the late 1960s and early 1970s brought new vigor to the voice type. Much closer in quality to the modern-day countertenor than Alfred Deller's falsetto, Bowman possessed a large, focused sound that fit comfortably into bigger opera houses in a way that a falsettist's voice never could. By the 1970s, Bowman was reclaiming repertoire that had been colonized by other vocal ranges.

Yet it wasn't until the 1990s, when David Daniels burst onto the opera scene, that countertenors truly broke the sound barrier. Daniels' surprisingly strong yet sensual sound excited both critics and audiences alike, and paved the way for the vocal style to re-emerge. Now, in addition to Daniels, there's an impressive roster of world-class countertenors reviving interest in baroque opera from San Francisco to Stuttgart‹including Andreas Scholl, Brian Asawa, David Walker, Daniel Taylor, Bejun Mehta, Jochen Kowalski, and Dominique Visse‹who possess true high-pitched voices that are full of power, beauty, and naturalness of tone, without sounding strained or artificial.

While baroque works remain the bread and butter of these artists, a surprisingly large number of new roles are being written for this voice type. The long list of composers who have written for countertenor includes John Adams, John Casken, Stewart Copeland, Jonathan Dove, Philip Glass, Hans Werner Henze, Meredith Monk, Arvo Pärt, Krzysztof Penderecki, Ned Rorem, Stewart Wallace, Judith Weir, and Hugo Weisgall, with over 200 new pieces composed in the last decade alone.

"Things have changed so much," says Daniels. "Every time I go to sing a recital at any university in this country, there are two or three countertenors in school as undergraduates. That was unheard of when I first started."

With a wealth of wonderful voices, and so many abandoned operas still waiting to be rediscovered‹Handel alone wrote 44‹the Golden Age of the Countertenor seems likely to shine for some time to come.