Formed in April 1987.
It's not entirely correct to say that Mortem became Arcturus, as Mortem continued for a long time after Arcturus was formed, with loads of different members within their ranks.
Mortem even reformed in the mid-nineties with a new line-up (without Steinar).
Now the debut album came out for Peaceville Records.
Now they release a compilation including the 1989 demo "Slow Death" and the re-recording version of this demo with bonus tracks.