Following the departure of former bassist/vocalist Martin VanDrunen, guitarist Patrick Mameli took over vocal duties. Mameli steered the band towards a more melodic and technical approach. The resulting concept album, Testimony of the Ancients contrasted brutal death metal riffs with melodic interludes and tackled what John Serba describes as, "strangely philosophical, and oddly compelling, subject matter". After each song on the album, there was an instrumental outro track. This attempt to push the boundaries of death metal, at a time when the scene was saturated with copycat "one track minded" bands, mirrored the efforts of fellow progressive bands Atheist and Death who released Unquestionable Presence and Human respectively in 1991, the same year as Testimony. The album can also be seen as a stepping stone on the way to the following Pestilence album Spheres, which departed still further from traditional death metal and headed towards jazz fusion.