Conversation so far:
When was Led Zeppelin IV released?
CANNOTANSWER.
How successful was it?
The album was a massive instant seller.
It entered the UK chart at No.
10, rising to No.1 the following week and.
How did it do after it's first week?
and stayed on the chart for 90 weeks.
In the US it stayed on the charts longer than any other Led Zeppelin album.

Question: How were the reviews?
Self-contained rewrite: How were the reviews for Led Zeppelin IV?