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The St. Louis Jesuits are coming home one last time. On Sunday afternoon, the Feast of St. Michael and All Angels, the five surviving members of what member Roc O’Connor calls “a fraternity of composers” — who together have influenced Roman Catholic liturgical music for over 40 years — will gather at Powell Symphony Hall for a final concert.

Now aged 68 to 80, O’Connor, Dan Schutte, Tim Manion, Bob Dufford, John Foley and the late John Kavanaugh met as Jesuit seminarians at St. Louis University in the early 1970s. They’d been writing separately; now they worked together. Their style reflected folk and popular music and the liturgical changes of the Second Vatican Council.

As they finished at SLU and were assigned elsewhere, they decided to lay down some tracks. “We found some singers, and small groups of us started recording,” O’Connor says. “We distributed them out of the residence hall. We thought that was it.”

Then a music publishing group, North American Liturgy Resources, offered to distribute their music. They were advised to keep writing and recording, “and somehow that got put into action,” he says.

The original quintet and some novices “went out to Berkeley, Calif., and wrote,” O’Connor recalls. “We shared our music each night, talked about it, gave comments.”

That led to the 1975 session that produced “Earthen Vessels.” “We brought in a ton of music and put down basic tracks on 30 songs,” he says. “There were 12 that really worked.”

“Earthen Vessels” sold more than a million copies, winning them the first of five Grammy nominations. People bought their cassettes, giving the music a life outside the church.

Scattered across the country, they’d compose during the year and meet up in the summer to record. “We all had other jobs, other studies, other assignments,” O’Connor says. “But there was this desire, even urge, to keep composing songs for the liturgy.”

The group took a break from 1984 to 2004, its members producing their own collections in the meantime. They last recorded together in 2004, with “Morning Light” appearing in 2005. Their occasional concerts are benefits, like Sunday’s for the Ignatian Spirituality Project. They’ll be backed up by the St. Francis Xavier College Church Choir

Most of their music is “choir songs; you could join in with them,” O’Connor says. “The goal was (to assist) the prayer of the faithful, the church gathered together, and, through word and melody, to create and help foster that space of engagement with God’s self and others. What we wanted to do, consciously, from the beginning, was to compose songs for the liturgy that could create a milieu of prayer.”

For this final sold-out concert, “it’s important to celebrate with thanksgiving these years. It’s important to celebrate by giving thanks to God and the people of God who will be there. We have more work to do: more labor, more prayer, more understanding, more going into the depths to find the places where God meets us in our individual and corporate lives.”

When they started, “the big questions seemed to be about the future of liturgy and liturgical music.” Their oeuvre was and remains controversial with traditionalists, but it has largely prevailed in American Catholicism. “It seems like what we came to do,” O’Connor says, “was the planting of a seed. We hope it grows and lasts beyond us.”

What “The St. Louis Jesuits — Coming Home” • When 3 p.m. Sunday • Where Powell Symphony Hall, 718 North Grand Boulevard • How much Sold out • More info 314-534-1700; slso.org