Steeleye Span: Gaudete

I was in Sainsbury's this time last year when Gaudete came on. I groaned.

Then I realised:

1. I really like it;
2. It was then 45 years since it had been in the charts;
3. A lot of the people around me weren't even born then so it will be a novelty to some readers.

Wikipedia explains that Gaudete dates from the 16th century and is doubly rare in being a UK hit single (it reached no. 14 at Christmas 1973, trailing behind Slade and Wizzard) that was a capella and sung in Latin.