Gregorian is a German band formed by Frank Peterson, known for their unique blend of Gregorian chant-inspired versions of modern pop and rock songs. Originating in 1991 and re-emerging in 1998, the group initially attempted a pop-oriented style similar to Enigma with their album "Sadisfaction." However, it was in 1998 that Peterson reinvented Gregorian to focus on chant-inspired renditions of popular songs, a concept that proved highly successful.

The band features a distinctive style that combines vocal harmony with instrumental accompaniment, performed by a group of twelve vocalists, including session and choir singers. These vocalists record their parts in a church-like atmosphere to maintain the authentic feel of Gregorian chants. Over the years, Gregorian has released numerous albums, primarily covering well-known songs in their signature style, and has occasionally included original compositions.

Gregorian's discography includes themed albums such as "The Dark Side," "Christmas Chants," and "Epic Chants." They are celebrated for their originality and willingness to experiment while maintaining a consistent musical mood. The band has toured extensively across Europe, China, Russia, and North America, captivating audiences with their unique sound and monastic stage attire.

Throughout their career, Gregorian has maintained a strong presence in the music industry, marked by their participation in events like the German national selection for the Eurovision Song Contest 2016. Their enduring appeal is reflected in their continued touring and the release of special editions celebrating their 25-year legacy.