DENVER — Much of the art of the medieval period, from poetry to great cathedrals, has come to us without attribution. Feminist art historians even joke that "Anonymous" was a woman. So when Susan Hellauer, Ruth Cunningham, Marsha Genensky, and Johanna Maria Rose in 1986 formed their voice ensemble for early music, Anonymous 4, drawing their name from an important unsigned medieval musical manuscript, the evocative name slipped on neatly.
Anonymous 4 can't miss: They transport the listener back hundreds of years to another world. Most, though not all, of their music is sacred, offering an island of serenity in a sea of 20th-century noise - a respite from contemporary stress. The more one listens, the purer the sound seems.
Their CDs consistently hit the top of classical charts (their latest, "11,000 Virgins, Music by Hildegard von Bingen," was third on Billboard's Top 10 for 15 weeks), and their concerts sell out. Their audiences come from all walks of life and religious (or secular) persuasions, and the attraction is profound and lasting. "The audience is much broader-based than only religious people," says Ms. Rose. "Just like people listen to Bach cantatas who are not Lutheran."
Asked about the challenges medieval music offers the group, Rose says, "It takes a great amount of control and accuracy. There is nowhere to hide. No one up there but the four of us. No orchestra, piano, nothing to support us."
"One of the main challenges is that the sources for medieval music don't give the performer nearly as much information about how to perform them as later sources do," says Ms. Hellauer. "Information about absolute pitch, expression, tempo, rhythm, all those things, are missing from medieval manuscripts. You get the notes and you get the text and sometimes the way those line up. Sometimes even that is in question."
Fortunately scholars - including Anonymous 4 themselves - are constantly finding new information about medieval music. And there is a new openness among medieval musicologists, Hellauer says. "They are more willing to communicate their discoveries. They are on e-mail, they are on the Internet.... Medieval musicology is one of those areas where you need to be a liturgist, a linguist, a historian, and an art historian as well as a musicologist."
The very challenges mean a different kind of satisfaction for the performers: Interpretation is by no means spelled out, says Ms. Genensky.
"It becomes your intuition, musicianship, and your desire to communicate," says Rose. "And we can't possibly try to create something from the Middle Ages. Basically, we are taking music from the Middle Ages and performing it as 20th-century musicians."
"The reward for [all the difficulties] is a greater use of one's own creative capacity to fill in the blanks," says Hellauer.
Their primary teacher, they say, is the music itself. "There is something that goes beyond what is quantifiable," says Hellauer. "There is a blend we achieve, and once the blend is cooking, it's not a matter of a little less vibrato here or more there. It's just 'on.' "
When they first started singing together, they would sing a variety of works from different cultures and periods. "Everyone was nervous about not boring the audience," says Hellauer. "And there would be applause between motets. There was no overall lasting impression. So we tried to put something together that was evocative of the context [that the music] might have been performed in [which may include a narrative]. And we try to make a progression of works that illustrates one style, place, person, or story so people would come away with a whole, integrated experience.
"We try, to some extent, to re-create that feeling like when we hear a Christmas carol: This is the way it felt during a special day in the Middle Ages."