At least once a year, producer Frank Peterson retreats with his headphones to raid his extensive music collection in the search for new repertoire. It takes a lot of instinct and inspiration to choose the songs for a project like Gregorian. "Not every song is suited for the Gregorian sound scale," he explains, "so the songs have to be chosen very carefully for Gregorian." Luckily, Peterson's immense music knowledge seems inexhaustible and there are no limits to his creativity. How else could it be that we find a Eurythmics ballad next to a Tears For Fears pop tune in the Gregorian repertoire? Or a Peter Gabriel song next to a Lenny Kravitz rock track? However, with Gregorian all of this fits in and forms a unit - well-known melodies in a completely new sound transporting the listener into the timeless world of Gregorian chant.

In 1998, Frank Peterson and his team re-invented what was initially a pop group into one that performs popular songs in the Gregorian style. The criteria for song selection were strict; in order to be considered, a song needed to be translatable into the 7-tone scale. After the songs were chosen, twelve vocalists - previously acclaimed session singers - were hired to form a choir.

The concept proved to be successful, and the group proceeded to record several more Masters of Chant albums in the same style. Their 2004 album, The Dark Side, was a slight departure from the others, featuring a darker repertoire consistent with the title. In 2005, The Masterpieces, a compilation album with a live DVD, was released.

A sixth Masters of Chant album was released on September 28, 2007.