This Saturday, January 12, one of best vocal groups you’ve never heard of, Cappella Romana, is performing Sergei Rachmaninoff’s The Liturgy of St. John Chrysostom (1910) at Holy Rosary Church in West Seattle. It’s their only Seattle appearance, and their performances of last season’s Vespers (also by Rachmaninoff) sold out, so you may want tickets ($27-$41) in advance.

Though it’s sung in Church Slavonic — Тебе поем means “We praise thee” — Orthodox Church authorities were not impressed.

Rachmaninoff’s music for the Orthodox Eucharist was too “modernist,” they felt, and they refused it permission to be performed as a church service. (Music in Russian churches is still a fraught issue today.) Things got even more modern with the coming of the 1917 Russian Revolution, which did nothing to improve the chances of church music, even by Rachmaninoff, being performed.

The “Divine Liturgy” languished for most of the twentieth century, only getting a revival in the late 1980s. Cappella Romana will present its twenty movements over two hours, with the declamations of both deacon (sung by Adam Steele) and priest (sung by John Michael Boyer). There are three solo passages and two for double choir (the Lord’s Prayer and the Beatitudes).

“It could hardly be called a performance,” wrote reviewer Philippa Kiraly of the group’s performance of Rachmaninoff’s Vespers. “It’s a devout religious experience for the singers, who when it was originally sung were always monks. Yet today, it takes profound scholarly knowledge to be able to sing it, which Cappella Romana has.” Expect a similar transport at this Saturday’s concert.