They were founded in 2001 by friends Mariusz Duda, Piotr Grudziński, Piotr Kozieradzki and Jacek Melnicki, who shared a love for progressive rock and heavy metal, although Duda, the main lyricist and composer of the band, was originally a fan of electronic, ambient, experimental music, like Radiohead, Massive Attack, Dead Can Dance, Tangerine Dream, Peter Gabriel,[1] and later on, prog rock like Pink Floyd, Rush, Tool, Marillion, as well as thrash metal.

[2] Riverside can be described as a blend of atmospheric rock and metal elements, resulting in a sound similar to that of Porcupine Tree, and Pain of Salvation.

Mariusz Duda, multi-instrumentalist and vocalist from the band Xanadu, agreed to attend a rehearsal in late fall of 2001 at the request of Jacek.

As the band continued to write more material for an album release, there grew a dissonance between keyboardist Jacek and the other members of Riverside.

The success of the album in Poland and the live shows that the band performed led to a release of the album on American record label Laser's Edge in September 2004, this time with cover art from Travis Smith, painter for bands such as Opeth, Katatonia, Anathema, and Devin Townsend.

Following their 2003 debut Out of Myself and the success that followed in 2004, the band began working on an EP entitled Voices in My Head which was at first a release exclusive to Poland through the label Mystic Production.

The band were taken in by major prog label Inside Out, releasing Second Life Syndrome in late October 2005.

[3] In 2006, Voices in My Head, the EP originally released in Poland only, was re-released under the InsideOut label, now revamped with the inclusion of three high quality live tracks off the Out of Myself album.

Mariusz Duda released the self-titled debut album from his new project Lunatic Soul by Kscope on 13 October 2008.

Anno Domini High Definition became the best selling album in Poland during its second week on the charts, following a debut at sixth place.

The album was recorded as a trio with Duda on vocals, bass and rhythm guitar parts, Kozieradzki on drums and Łapaj on keyboards and hammond, plus some guest musicians.

The style is heavier than the predecessor, that there is black metal riffs, slower paces, and the melodies would take on a Slavic flavor.

Mariusz also talked about the influence of road movies and westerns, as well as games from the Fallout series, which fit well with the post-apo world and would help define the stylistic layer and mood of the album.

[16] On 3 February 2020, Riverside announced that Maciej Meller had joined the band in an official capacity and would be involved in the writing sessions for their eighth album.

Three singles from the album, "Friend or Foe", "Self-Aware" and "I'm Done with You" were accompanied by official music videos, published on YouTube.