Ágætis byrjun is the second studio album by Icelandic post-rock band Sigur Rós, released on 12 June 1999. The album was recorded between the summer of 1998 and the spring of 1999 with producer Ken Thomas. Ágætis byrjun represented a substantial departure from the band's previous album Von, with that album's extended ambient soundscapes replaced by Jónsi Birgisson's cello-bowed guitar work and orchestration, using a double string octet amongst other chamber elements.