Conversation so far:
What is the name of Renaissance's hit single?
They are best known for their 1978 UK top 10 hit Northern Lights
How did Northern Lights do in the charts?
Northern Lights entered the UK singles charts on 15 July 1978 and remained there for 11 weeks, peaking at No. 10
What label were Renaissance with when it was produced?
Label. Warner Bros, Sire.

Question: How many albums did they sell?
Self-contained rewrite: How many albums of A song for All Seaons with the single Northern Lights did the band Renaissance sell?