There are multiple artists with this name:
1) A norwegianprogressive metal band.
2) An american 60's psychedelic rock band. 1)
Circus Maximus is a progressive metal band from Oslo, Norway. In 2000 long-time band mates Michael Eriksen (vocals) and brothers Mats (guitar) and Truls Haugen (drums) were joined by keyboard genius Espen Storø and Glen Cato Møllen on bass to form Circus Maximus. Initially being a cover band, they got a lot of positive feedback for their interpretations of technically challenging material like songs of Dream Theater and Symphony X.