BRAINTREE -- To celebrate Cardinal Seán P. O’Malley’s 25th anniversary of episcopal ordination, Gloriae Dei Cantores, the 40-voice choir from Cape Cod, will perform at the Cathedral of the Holy Cross in Boston on Sept. 24 at 8:00 p.m.

The concert is free and open to the public. Donations to support the Choir will be accepted.

Gloriae Dei Cantores will perform the work of 20th century Russian composer Georgy Sviridov, who entrusted his six-movement “Ineffable Mystery” to Gloriae Dei Cantores after hearing the choir sing this music of the Russian Orthodox Church.

The remainder of the concert program includes Gregorian chant, excerpts from the “Liturgy of St. John Chrysostom” by Tchaikovsky, Rachmaninoff’s “All-Night Vigil,” American composer Howard Hanson’s “Cherubic Hymn”, the “First Nocturne of the Tenebrae,” Op. 72, by English composer Edmund Rubbra, and Frank Martin’s “Mass for Double Choir.”

The tour coincides with the release of Gloriae Dei Cantores’ newest CD, “Unto Ages of Ages: Sacred Choral Music of Sviridov, Rachmaninoff and Tchaikovsky,” featuring “Ineffable Mystery,” excerpts from “The Liturgy of St. John Chrysostom,” and the “All-Night Vigil.”