Starting out in 1996 as a Metallica jam band with the line-up Jesper (guitar/vocals), Ryan (guitars) and Andreas (drums), with Dan joining in on bass guitar shortly later, Compos Mentis would take their influences from Cradle Of Filth, Dark Tranquility, Withering Surface and Moonspell, influences that changed their style to more like Melodic Death/Black Metal.
In spring 1999, after having recorded Vulturous, they decided that keyboards would hit the spot, and Bo joined in on keyboards. A few months later they were offered to participate on Extremity Rising Vol. 4, a compilation disc from the Danish label Serious Entertainment'. They contributed the track Brave And Lonely and Extremity Rising Vol. 4 was released in the autumn of 1999.
From the 14th till the 16th April 2000 they recorded a new four track-demo, Quadrology Of Sorrow. Their debut full-length album Fragments Of A Withered Dream arrived on Lost Disciple Records' on the 3rd of January 2003.