After drafting teenaged mezzo-soprano Simone Simons, guitarist Ad Sluijter, keyboardist Coen Janssen, bassist Yves Huts, and drummer Jeroen Simons, Epica entered Wolfsburg, Germany's Gate Studio with a classically trained choir and string section to lay down their ambitious debut, The Phantom Agony. Released by Transmission Records in late 2003, the album spawned a number of singles.

The band's early success paved the way for 2005's sophomore LP, Consign to Oblivion, which also charted well in the Netherlands. A move to metal powerhouse Nuclear Blast and the addition of Ariën van Weesenbeek on drums was followed by Epica's first conceptual album, The Divine Conspiracy, released in 2007. It charted across Europe, as did 2009's Design Your Universe, which equaled their best Dutch chart showing at number eight; Design Your Universe also featured a new member, with Isaac Delahaye taking over guitar duties.

Epica's fifth studio album, Requiem for the Indifferent, appeared in 2012. It was the first to chart in the U.K. and U.S., after which another lineup shift found Huts giving way to Rob van der Loo on bass. The band celebrated its tenth anniversary in March 2013 with a special show in Eindhoven, titled and later released as Retrospect, which even featured former members Sluijter, Simons, and Huts. Just a year later, the band issued The Quantum Enigma, its first studio album with Rob van der Loo. Epica's next full-length outing, 2016's Holographic Principle, was described by Simons in an interview with Spark TV as their "most ambitious offering to date." ~ Eduardo Rivadavia