MCMXC a.D. is the debut studio album by the German musical project Enigma, led by Romanian-German musician Michael Cretu. It was released in Europe by Virgin Records on 3 December 1990, and in the United States by Charisma Records on 12 February 1991. Cretu became fascinated with mixing archaic sounds with modern music after producing German pop singer Sandra's song "Everlasting Love", for which he experimented with Gregorian chant. Following Michael Cretu and Sandra's marriage in 1988, Michael developed the idea of the musical project Enigma and recorded the album over the course of eight months in 1990 at A.R.T. Studios.

"Sadeness (Part I)" is a song by German musical project Enigma, released in October 1990 by Virgin Records as the lead single from their first album, MCMXC a.D. (1990). It became an international hit, reaching number one in 14 countries. In the United States, the song peaked at number five on the Billboard Hot 100 and number one on both the Dance Club Play and 12-inch Singles Sales charts. Its music video was directed by Michel Guimbard. A sequel to the song, "Sadeness (Part II)" featuring Anggun, was released on Enigma's eighth studio album, The Fall of a Rebel Angel (2016).