Conversation so far:
Were Morbid Angel's albums a success?
Morbid Angel's first four albums – Altars of Madness, Blessed Are the Sick, Covenant and Domination – are considered classics in the genre.
Did any of Morbid Angel's albums win awards?
According to Nielsen Soundscan, Morbid Angel's Covenant was the best selling death metal album as of 2003.
Were there any influences in the making of Morbid Angel's albums?
From Morbid Angel's Formulas Fatal to the Flesh onward, via Azagthoth's influence, the lyrics moved toward the ancient Sumerian gods.
Are there any other interesting aspects about Morbid Angel besides the lyrics moving toward the ancient Sumerian gods?
Morbid Angel's first studio album, Altars of Madness, was released in 1989, and is regarded by many as one of the most important death metal albums of all time.

Question: Why is it regarded as one of the most important?
Self-contained rewrite: Why is Altars of Madness by Morbid Angel regarded as one of the most important death metal albums of all time?