Conversation so far:
When was Sandy Denny in the band Fairport Convention?
Denny became the obvious choice.
who else was in the band with her?
Simon Nicol.
did they release an album?
three albums.
when was the first album released?
What We Did on Our Holidays.
what was the name of the second album?
Unhalfbricking.
what was the name of the third album?
Liege & Lief.

Question: when did she join Fotheringay?
Self-contained rewrite: When did Denny join Fotheringay?