44 years ago this week. Crosby Stills and Nash released their first album as a trio. There are conflicting stories of how these alumni of Buffalo Springfield and the Hollies got together, but the one I like best is that it happened at a party at the home of Mama Cass Elliot. It is said that she heard them harmonizing as rock musicians often did back in the day, and suggested that they ought to make a record.

Before they knew it, they had a gig, performing at the legendary Woodstock Music and Art Fair, the one we all saw on the big screen in 1969. And here’s what happened.