Complex sentence: The band enjoyed a somewhat meteoric rise to success following the release of their eponymous debut album in 1999, and the 2001 follow-up album, "Iowa", further increased the band's popularity.
Split into simpler sentences: The band enjoyed a somewhat meteoric rise to success following the release of their eponymous debut album in 1999. The 2001 follow-up album, "Iowa", further increased the band's popularity.