Complex sentence: During the 1970s, Mushroom released several successful albums from artists such as Doucette, Heart and Chilliwack, but Siegel's sudden death due to aneurysm on 17 January 1979 led to the demise of the label.
Split into simpler sentences: During the 1970s, Mushroom released several successful albums from artists such as Doucette, Heart and Chilliwack. But Siegel's sudden death due to aneurysm on 17 January 1979 led to the demise of the label.