While Colosseum lasted only a little more than three years, producing five albums in that time, they made a great impression on the blooming subgenre of progressive rock, first with the energetic jazz- and blues-influenced Those Who Are About to Die Salute You, with its unusual chord progressions and variant song structures, and then with the epic Valentyne Suite. The title track of Valentyne Suite, a 17-minute composition, pushed keyboardist Dave Greenslade to the forefront of the band and into the spotlight of progressive music, a position he was increasingly uneasy with over the years. Drummer Jon Hiseman, on the other hand, gradually moved towards the jazz fusion area. Colosseum began to undergo personnel shifts with their third album, Grass Is Greener, with everyone calling it quits upon the departure of Greenslade in 1971. In 1975, Hiseman formed Colosseum II, but this time the mandate was firmly jazz fusion.