The “Missa Solemnis” is not performed very often. But it happens to be one of Marvin’s favorite works, and the leaders of the three singing groups chose to perform it partly for that reason.

No one is more aware of the piece’s complexity than Marvin himself. “He set us down and talked it through with us at the beginning of the year,” Schmidt said.

The “Missa Solemnis” sets a traditional Catholic Mass text to music, “but not for use in service, instead for concert use,” Schmidt said.

It is divided into five different movements: the Kyrie, the Gloria, the Credo, the Sanctus and the Agnus Dei. The first two are generally known for following a more classical style of church music, whereas the last three have more dramatic elements not found in most traditional religious music.

Each student group has rehearsed parts of the “Missa Solemnis” separately. Throughout the year they have been gradually working up to tonight’s concert, which also features professional singers and guest conductors not affiliated with Harvard.

Barbara H. Urbanczyk ’03, the former Vice President of the Radcliffe Choral Society, says that the concert is a “morale booster.”

“It was a grueling process, but we’re all excited about singing the ‘Missa Solemnis’,” Urbanczyk said.

Tonight’s concert kicks off a weekend of events, including numerous alumni gatherings organized by the Glee Club Foundation, the HRCM Foundation and Friends of the Radcliffe Choral Society.

Marvin will conduct all three groups in a performance of the Brahms Requiem Saturday afternoon, followed by a banquet in Eliot House.

According to Sarah P. Cove ’04, president of HRCM, one of the things that distinguishes this commemoration of Marvin’s work is the alumni participation.

“It’s really a remarkable thing,” Cove said. “There’s such a high level of alumni involvement, and they’re all excited to be coming back.”

Yeh, who managed one of the HRCM’s international tours during her years at Harvard, said that about 200 alumni of RCS, Glee Club and Collegium are returning from across the country and around the world.

Cove calls it “a weekend full of singing and honoring Jim.”

Both current and past members of the three singing groups emphasize Marvin’s remarkable contributions to choral activities at Harvard, saying that almost everyone has the chance to work closely with him through rehearsals and concerts.

“He always wants the best for his students. Though it has been frustrating at times, I think that he’s brought the level of singing to the highest it’s been at Harvard,” Yeh said. “He’s a perfectionist—he always wants the best but also makes it fun. “

—Staff writer Tiffany I. Hsieh can be reached at tihsieh@fas.harvard.edu.