MCMXC a.D. is the debut studio album by the German musical project Enigma, led by the Romanian-German musician Michael Cretu.

Cretu became fascinated with mixing archaic sounds with modern music after producing "Everlasting Love" by the German pop singer Sandra, for which he experimented with Gregorian chant.

MCMXC a.D. combines new-age music with dance rhythms, Gregorian chant and themes of religion and sexuality, for which it received generally positive reviews.

[9] Despite having virtually no promotion, "Sadeness (Part I)" became an international hit and reached number one in Germany faster than any previous new release, and prior to the completion of its music video.

[8] The three producers were credited on MCMXC a.D. under the same monikers as on "Sadeness (Part I)": Cretu as Curly M.C., Peterson as F. Gregorian, and Cuitad as David Fairstein.

[5][17][18] The album is well known for its mixing of Gregorian chant and other religious overtones with sexuality;[19] the lead single, "Sadeness (Part I)", being the prime example.

[21] After the foghorn, Louisa Stanley (an executive at Virgin Records at the time) starts talking[21] and invites the listener to relax and take a deep breath,[17] while an environmental soundscape plays in the background.

[13] The song's French lyrics are a quizzical look at, and defense of, the 18th-century writer Marquis de Sade, who was notorious for writing literature delving into themes of sexual violence and domination.

[24] "The Voice & the Snake" is based on the Book of Revelation[25] and was sampled from "The Seven Bowls," which is the eighth track on the final album of the prog-rock band Aphrodite's Child, 666, released in 1972.

[30][31] The song charted at number four in France,[32] and received a gold certification from the French National Syndicate of Phonographic Publishing (SNEP).

Danny Serbib of Colorado Springs Magazine said that by adding Gregorian chant to the album, "[Cretu had] redefined the possible future of popular music.

"[43] AllMusic critic Ned Raggett said, "Michael Crétu's attempt at fusing everything from easy listening sex music and hip-hop rhythms to centuries-old Gregorian chants could not have been more designed to tweak the nose of high art.

"[17] Marisa Fox wrote, for Entertainment Weekly, that while the album doesn't have as many accessible hits as other ones, "[the] journey through what the group calls 'music, spirit, and meditation' is entrancing as well as provocative.

"[16] In contrast, Brian Bourke, in the Syracuse Herald-Journal, stated that "once the novelty of Enigma's approach wears off", the rhythms underneath the songs have a sameness that is "irritating" in his eyes, with the exception of "The Rivers of Belief".

[26] The Village Voice critic Robert Christgau asserted that the "mellow electrobeat and Gregorian fog" of "Sadeness (Part I)" "provide[s] mutual relief", and suggested the other songs are disco filler with sexual content that is too lacking in vulgarity for his tastes.

[28] The album spent 46 weeks on the German chart,[28] and has been certified double platinum by the Bundesverband Musikindustrie (BVMI), indicating shipments in excess of one million copies in Germany.

[48] The album has since been certified quadruple platinum by the Recording Industry Association of America (RIAA), denoting shipments in excess of four million copies in the US.

[11] Cretu stated that he did not mean for there to be any implications of Satanism with the album, revealing he wanted the combination of Gregorian chant and lyrics relating to the Marquis de Sade to be seen as a paradox.

The lawsuit was settled out of court after Virgin publicly apologized for the infringement and Cretu agreed to pay compensation to the original creator of the samples.