When Britten’s War Requiem was premiered in the United States in 1963, it featured Chorus pro Musica performing with the Boston Symphony Orchestra at Tanglewood, under the direction of Erich Leinsdorf. Now, at the instigation of conductor Richard Pittman and his New England Philharmonic, Chorus pro Musica once again is taking part in a “coming together in an homage to peace” with two other musical organizations — the Boston Children’s Chorus and the Providence Singers — to honor the end of the nine-year war in Iraq. The Boston performance is at the Cathedral of the Holy Cross, in Boston’s South End, on Saturday, March 3, at 8 pm.

Benjamin Britten’s War Requiem was commissioned for the consecration in 1962 of England’s new Coventry Cathedral, the original of which was bombed to a shell by the Luftwaffe during World War II. But the source of the libretto recalled World War I, the horrible “war to end all wars.” The text intersperses the timeless words of the Latin Mass for the Dead with the poetry of Wilfred Owen, a World War I British soldier who was killed a week before the Armistice.

This upcoming concert, a year in the planning, is hardly a new collaboration. The Chorus pro Musica and New England Philharmonic have performed together for each of the three years since Betsy Burleigh became director of one of Boston’s most prestigious choruses. As a graduate student at NEC, she took Pittman’s class in orchestral conducting. The Providence Singers came into the picture when Burleigh, who knew that larger forces were needed, became director of the group last summer.  Soloists are tenor Frank Kelley, baritone Sumner Thompson, and soprano Sarah Pelletier. The Boston Children’s Chorus, with its outstanding position in the Boston community, was a natural for the youth choral sections of the Requiem. In all, the performance will have more than 300 orchestral musicians and singers. Very few places can accommodate that large a group, but the Cathedral of the Holy Cross in Boston’s South End fits the bill.

The New England Philharmonic created the monumental plan for these concerts in acknowledgement of its 35 years of presenting recognizably well programmed concerts in greater Boston. Pittman explained, “For each anniversary we try to find a piece; we have done Wozzeck on our 30^th anniversary, Bluebeard’s Castle on our 25^th. Britten’s War Requiem is widely admired and seemed appropriate at this time.”

The Boston Children’s Chorus, singing antiphonally, will be in the choir loft at the back of cathedral. The Cathedral’s original 1875 organ, however, is at the wrong pitch, Pittman noted.  “So we have hired two men to deliver a portative up a spiral staircase two stories high. Not only that, but because we are borrowing the instrument, it has to be carried in and out again for each performance. Let’s hope these two same guys show up each time!”

 Pittman said of the  War Requiem, “I think first of all, of course, it is great work, and musically speaking, so unusual in combining in a brilliant way the traditional Latin Requiem with poetry of Wilfred Owen,” set to music by a steadfastly pacifist composer.

“The baritone and tenor are always accompanied by a chamber orchestra; the soprano always sings in Latin with the full orchestra,” Pittman explained, “and the children’s choir is off on its own, accompanied by its own organ.”

The “Dies Irae,” the second movement, is the longest of the six movements, Pittman pointed out. “It has so many parts that it reminds me a bit of the finales of Mozart’s operas. Extraordinary. His musical constructions begin with an aria that moves without a break to a duet or a trio with completely different music that still connects, often in a different tempo and different key, then to an ensemble of four people — new musical material without a break.

“The Britten ‘Dies Irae’ is the same way, starting off with brass fanfares, a demonic fanfare from a chorus in 7/4, then more fanfare, interrupted by the baritone singing ‘Bugles sang’; but this is mournful, about the tragedy of soldiers dying. That leads to the section with the soprano and full orchestra, measured and lyrical, then to a militaristic, boisterous duet by tenor and baritone, once again with chamber orchestra, talking about their defiance of death…  Then, once again, a very slow, lyrical section for the women of the chorus with full orchestra, then a faster section for just the men… The basses sing militaristically, ‘Confutatis maledictis,’ and the tenors sing lyrically against it, ‘Oro supplex’, combined!  The baritone with chamber orchestra sings of slowly lifting up “long black arm” – a canon, each phrase interspersed with a trumpet fanfare…. The 7/4 with trumpets and chorus comes back, and then slows down into a ‘Lacrimosa’ with chorus and soprano, quite mournful, followed once again with the tenor singing of moving a dying soldier into the sunlight; this is interspersed with ‘Lacrimosa.’ The ‘Dies Irae’ ends with ‘Pie Jesu Domine’ from the a cappella chorus.”

The 1930s in Britain were not easy years  for a committed pacifist. Britten’s treatment of war, tempered by the poetry of Wilfred Owen, two world wars, and the Cold War gloom of nuclear arms, was not celebratory.  “When you hear Britten’s music — if you really hear it, not just listen to it superficially,” said Leonard Bernstein, “you become aware of something very dark. There are gears that are grinding and not quite meshing. And they make a great pain.  It was a difficult and lonely time.”

Burleigh is thrilled to be part of this performance. “When I was a student in Boston, I heard it [The War Requiem] live at the BSO. Britten had an extraordinary ability to capture both the drama and psychology in this setting, for an extremely expressive, extremely powerful work. Over the years, as I have been working with choruses, I have never been part of it. I thought, it is not going to happen in my lifetime.”

There will be a repeat performance on March 4^th at 3:30 pm at Providence’s Cathedral of Saints Peter and Paul.